diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 5fbe2eb113..e6beafe1bb 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -321,6 +321,7 @@ jobs:
             install_steps: skiprun mbedtls-latest-intel rustls wolfssl-opensslextra-intel
             install_steps_brew: openssl@4 gsasl
             CC: clang-20
+            CFLAGS: -Wunused-macros
             LDFLAGS: >-
               -Wl,-rpath,/home/runner/wolfssl-opensslextra/lib
               -Wl,-rpath,/home/runner/mbedtls/lib
@@ -345,6 +346,7 @@ jobs:
             install_steps: skiprun
             install_steps_brew: libngtcp2 libnghttp3 c-ares
             CC: clang-20
+            CFLAGS: -Wunused-macros
             LDFLAGS: >-
               -Wl,-rpath,/home/linuxbrew/.linuxbrew/opt/openssl/lib
               -Wl,-rpath,/home/linuxbrew/.linuxbrew/opt/libngtcp2/lib
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index e0250f5624..f3d71cdf47 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -300,6 +300,7 @@ jobs:
             compiler: clang
             install: llvm gnutls nettle libressl krb5 mbedtls gsasl rustls-ffi libssh fish
             install_steps: skiprun
+            CFLAGS: -Wunused-macros
             chkprefill: _chkprefill
             generate: >-
               -DCURL_USE_OPENSSL=ON -DOPENSSL_ROOT_DIR=/opt/homebrew/opt/libressl -DCURL_DEFAULT_SSL_BACKEND=openssl
@@ -316,6 +317,7 @@ jobs:
             compiler: clang
             install: llvm libnghttp3 libngtcp2 openldap krb5
             install_steps: skipall
+            CFLAGS: -Wunused-macros
             generate: >-
               -DCURL_USE_OPENSSL=ON -DOPENSSL_ROOT_DIR=/opt/homebrew/opt/openssl -DUSE_NGTCP2=ON
               -DLDAP_INCLUDE_DIR=/opt/homebrew/opt/openldap/include
@@ -445,6 +447,7 @@ jobs:
 
       - name: 'configure'
         env:
+          CFLAGS: '${{ matrix.build.CFLAGS }}'
           MATRIX_CHKPREFILL: '${{ matrix.build.chkprefill }}'
           MATRIX_CONFIGURE: '${{ matrix.build.configure }}'
           MATRIX_GENERATE: '${{ matrix.build.generate }}'
@@ -479,7 +482,6 @@ jobs:
               false
             fi
           else
-            export CFLAGS
             if [[ "${MATRIX_COMPILER}" = 'llvm'* ]]; then
               options+=" --target=$(uname -m)-apple-darwin"
             fi
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 67db3798fe..9074526bdb 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -782,7 +782,7 @@ jobs:
         include:
           - { build: 'autotools', compiler: 'gcc' }
           - { build: 'cmake'    , compiler: 'gcc' }
-          - { build: 'cmake'    , compiler: 'clang-tidy', install_packages: 'clang-20 clang-tidy-20' }
+          - { build: 'cmake'    , compiler: 'clang-tidy', install_packages: 'clang-20 clang-tidy-20', CFLAGS: '-Wunused-macros' }
     steps:
       - name: 'install packages'
         timeout-minutes: 2
@@ -801,6 +801,8 @@ jobs:
         run: autoreconf -fi
 
       - name: 'configure'
+        env:
+          CFLAGS: '${{ matrix.CFLAGS }}'
         run: |
           if [ "${MATRIX_BUILD}" = 'cmake' ]; then
             if [ "${MATRIX_COMPILER}" = 'clang-tidy' ]; then
diff --git a/lib/parsedate.c b/lib/parsedate.c
index ce358bd465..b19423169a 100644
--- a/lib/parsedate.c
+++ b/lib/parsedate.c
@@ -98,8 +98,12 @@ const char * const Curl_month[] = {
 
 #ifndef CURL_DISABLE_PARSEDATE
 
+#if SIZEOF_TIME_T < 5
 #define PARSEDATE_LATER  1
+#endif
+#if SIZEOF_TIME_T < 5 || defined(HAVE_TIME_T_UNSIGNED)
 #define PARSEDATE_SOONER 2
+#endif
 
 static const char * const weekday[] = {
   "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"
diff --git a/tests/libtest/first.h b/tests/libtest/first.h
index 9ed8a9c458..21da11394c 100644
--- a/tests/libtest/first.h
+++ b/tests/libtest/first.h
@@ -58,19 +58,23 @@ extern int unitfail; /* for unittests */
 #include <sys/select.h>
 #endif
 
+#ifndef UNITTESTS
 #define test_setopt(A, B, C)            \
   do {                                  \
     result = curl_easy_setopt(A, B, C); \
     if(result != CURLE_OK)              \
       goto test_cleanup;                \
   } while(0)
+#endif /* !UNITTESTS */
 
+#if 0
 #define test_multi_setopt(A, B, C)       \
   do {                                   \
     result = curl_multi_setopt(A, B, C); \
     if(result != CURLE_OK)               \
       goto test_cleanup;                 \
   } while(0)
+#endif
 
 extern const char *libtest_arg2; /* set by first.c to the argv[2] or NULL */
 extern const char *libtest_arg3; /* set by first.c to the argv[3] or NULL */
@@ -104,8 +108,10 @@ void ws_close(CURL *curl);  /* just close the connection */
  *
  * For portability reasons TEST_ERR_* values should be less than 127.
  */
-
+#if !defined(UNITTESTS) || defined(BUILDING_LIBCURL)
 #define TEST_ERR_MAJOR_BAD    CURLE_OBSOLETE20
+#endif
+#ifndef UNITTESTS
 #define TEST_ERR_RUNS_FOREVER CURLE_OBSOLETE24
 #define TEST_ERR_EASY_INIT    CURLE_OBSOLETE29
 #define TEST_ERR_MULTI        CURLE_OBSOLETE32
@@ -236,8 +242,10 @@ void ws_close(CURL *curl);  /* just close the connection */
     }                                                    \
   } while(0)
 
+#if 0
 #define res_multi_setopt(A, B, C) \
   exe_multi_setopt(A, B, C, __FILE__, __LINE__)
+#endif
 
 #define chk_multi_setopt(A, B, C, Y, Z) \
   do {                                  \
@@ -290,8 +298,10 @@ void ws_close(CURL *curl);  /* just close the connection */
     }                                                           \
   } while(0)
 
+#if 0
 #define res_multi_remove_handle(A, B) \
   exe_multi_remove_handle(A, B, __FILE__, __LINE__)
+#endif
 
 #define chk_multi_remove_handle(A, B, Y, Z) \
   do {                                      \
@@ -426,8 +436,10 @@ void ws_close(CURL *curl);  /* just close the connection */
     }                                                           \
   } while(0)
 
+#if 0
 #define res_multi_poll(A, B, C, D, E) \
   exe_multi_poll(A, B, C, D, E, __FILE__, __LINE__)
+#endif
 
 #define chk_multi_poll(A, B, C, D, E, Y, Z) \
   do {                                      \
@@ -456,6 +468,7 @@ void ws_close(CURL *curl);  /* just close the connection */
 #define res_multi_wakeup(A) \
   exe_multi_wakeup(A, __FILE__, __LINE__)
 
+#if 0
 #define chk_multi_wakeup(A, Y, Z) \
   do {                            \
     exe_multi_wakeup(A, Y, Z);    \
@@ -465,6 +478,7 @@ void ws_close(CURL *curl);  /* just close the connection */
 
 #define multi_wakeup(A) \
   chk_multi_wakeup(A, __FILE__, __LINE__)
+#endif
 
 /* ---------------------------------------------------------------- */
 
@@ -518,8 +532,10 @@ void ws_close(CURL *curl);  /* just close the connection */
 #define res_test_timedout() \
   exe_test_timedout(TEST_HANG_TIMEOUT, __FILE__, __LINE__)
 
+#if 0
 #define res_test_timedout_custom(T) \
   exe_test_timedout(T, __FILE__, __LINE__)
+#endif
 
 #define chk_test_timedout(T, Y, Z) \
   do {                             \
@@ -534,6 +550,15 @@ void ws_close(CURL *curl);  /* just close the connection */
 #define abort_on_test_timeout_custom(T) \
   chk_test_timedout(T, __FILE__, __LINE__)
 
+#define NUM_HANDLES 4  /* global default */
+
+#define res_global_init(A) \
+  exe_global_init(A, __FILE__, __LINE__)
+
+#endif /* !UNITTESTS */
+
+#if !defined(UNITTESTS) || defined(BUILDING_LIBCURL)
+
 /* ---------------------------------------------------------------- */
 
 #define exe_global_init(A, Y, Z)                        \
@@ -548,9 +573,6 @@ void ws_close(CURL *curl);  /* just close the connection */
     }                                                   \
   } while(0)
 
-#define res_global_init(A) \
-  exe_global_init(A, __FILE__, __LINE__)
-
 #define chk_global_init(A, Y, Z) \
   do {                           \
     exe_global_init(A, Y, Z);    \
@@ -564,13 +586,6 @@ void ws_close(CURL *curl);  /* just close the connection */
 #define global_init(A) \
   chk_global_init(A, __FILE__, __LINE__)
 
-#define NO_SUPPORT_BUILT_IN                     \
-  {                                             \
-    (void)URL;                                  \
-    curl_mfprintf(stderr, "Missing support\n"); \
-    return CURLE_UNSUPPORTED_PROTOCOL;          \
-  }
-
-#define NUM_HANDLES 4  /* global default */
+#endif /* !UNITTESTS || BUILDING_LIBCURL */
 
 #endif /* HEADER_LIBTEST_FIRST_H */
diff --git a/tests/libtest/lib1912.c b/tests/libtest/lib1912.c
index 98623bd339..65de8b3ffb 100644
--- a/tests/libtest/lib1912.c
+++ b/tests/libtest/lib1912.c
@@ -23,16 +23,17 @@
  ***************************************************************************/
 #include "first.h"
 
-#define print_err(name, exp)                                            \
-  curl_mfprintf(stderr, "Type mismatch for CURLOPT_%s (expected %s)\n", \
-                name, exp)
-
 static CURLcode test_lib1912(const char *URL)
 {
 /* Only test if GCC/clang type checking is available */
   int error = 0;
 #ifdef CURLINC_TYPECHECK_GCC_H
   const struct curl_easyoption *o;
+
+#define print_err(name, exp)                                            \
+  curl_mfprintf(stderr, "Type mismatch for CURLOPT_%s (expected %s)\n", \
+                name, exp)
+
   for(o = curl_easy_option_next(NULL); o; o = curl_easy_option_next(o)) {
     /* Test for mismatch OR missing typecheck macros */
     if(curlcheck_long_option(o->id) !=
diff --git a/tests/libtest/lib2301.c b/tests/libtest/lib2301.c
index 8d036682a4..dece3553a7 100644
--- a/tests/libtest/lib2301.c
+++ b/tests/libtest/lib2301.c
@@ -97,6 +97,8 @@ static CURLcode test_lib2301(const char *URL)
   curl_global_cleanup();
   return result;
 #else
-  NO_SUPPORT_BUILT_IN
+  (void)URL;
+  curl_mfprintf(stderr, "Missing support\n");
+  return CURLE_UNSUPPORTED_PROTOCOL;
 #endif
 }
diff --git a/tests/libtest/lib2302.c b/tests/libtest/lib2302.c
index ef8990fc17..7eb4931c5c 100644
--- a/tests/libtest/lib2302.c
+++ b/tests/libtest/lib2302.c
@@ -125,6 +125,8 @@ static CURLcode test_lib2302(const char *URL)
   curl_global_cleanup();
   return result;
 #else
-  NO_SUPPORT_BUILT_IN
+  (void)URL;
+  curl_mfprintf(stderr, "Missing support\n");
+  return CURLE_UNSUPPORTED_PROTOCOL;
 #endif
 }
diff --git a/tests/libtest/lib2304.c b/tests/libtest/lib2304.c
index fd2a29da6c..013a4de929 100644
--- a/tests/libtest/lib2304.c
+++ b/tests/libtest/lib2304.c
@@ -85,6 +85,8 @@ static CURLcode test_lib2304(const char *URL)
   curl_global_cleanup();
   return result;
 #else
-  NO_SUPPORT_BUILT_IN
+  (void)URL;
+  curl_mfprintf(stderr, "Missing support\n");
+  return CURLE_UNSUPPORTED_PROTOCOL;
 #endif
 }
diff --git a/tests/libtest/lib2700.c b/tests/libtest/lib2700.c
index e8199e0364..e093fa7266 100644
--- a/tests/libtest/lib2700.c
+++ b/tests/libtest/lib2700.c
@@ -249,6 +249,8 @@ test_cleanup:
   curl_global_cleanup();
   return result;
 #else
-  NO_SUPPORT_BUILT_IN
+  (void)URL;
+  curl_mfprintf(stderr, "Missing support\n");
+  return CURLE_UNSUPPORTED_PROTOCOL;
 #endif
 }
diff --git a/tests/libtest/lib518.c b/tests/libtest/lib518.c
index 5c50ca5cbf..e2c98db22d 100644
--- a/tests/libtest/lib518.c
+++ b/tests/libtest/lib518.c
@@ -23,6 +23,8 @@
  ***************************************************************************/
 #include "first.h"
 
+#if defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT)
+
 #include "testutil.h"
 
 #define T518_SAFETY_MARGIN 16
@@ -36,8 +38,6 @@
 #define DEV_NULL "/dev/null"
 #endif
 
-#if defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT)
-
 static int *t518_testfd = NULL;
 static struct rlimit t518_num_open;
 static char t518_msgbuff[256];
diff --git a/tests/libtest/lib537.c b/tests/libtest/lib537.c
index 82b92a02ad..9257eaf02e 100644
--- a/tests/libtest/lib537.c
+++ b/tests/libtest/lib537.c
@@ -23,6 +23,8 @@
  ***************************************************************************/
 #include "first.h"
 
+#if defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT)
+
 #include "testutil.h"
 
 #define T537_SAFETY_MARGIN 11
@@ -33,8 +35,6 @@
 #define DEV_NULL "/dev/null"
 #endif
 
-#if defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT)
-
 static int *t537_testfd = NULL;
 static struct rlimit t537_num_open;
 static char t537_msgbuff[256];
diff --git a/tests/server/dnsd.c b/tests/server/dnsd.c
index 9da4eefce8..aab3c8c251 100644
--- a/tests/server/dnsd.c
+++ b/tests/server/dnsd.c
@@ -159,13 +159,17 @@ static int blob_add_qname(struct blob *b, const struct Curl_str *str)
 #define QTYPE_AAAA  28
 #define QTYPE_HTTPS 0x41
 
+#if 0
 #define HTTPS_RR_CODE_MANDATORY       0x00
+#endif
 #define HTTPS_RR_CODE_ALPN            0x01
 #define HTTPS_RR_CODE_NO_DEF_ALPN     0x02
+#if 0
 #define HTTPS_RR_CODE_PORT            0x03
 #define HTTPS_RR_CODE_IPV4            0x04
 #define HTTPS_RR_CODE_ECH             0x05
 #define HTTPS_RR_CODE_IPV6            0x06
+#endif
 
 static const char *type2string(uint16_t qtype)
 {
diff --git a/tests/unit/unit1307.c b/tests/unit/unit1307.c
index 53377afdb9..833319b611 100644
--- a/tests/unit/unit1307.c
+++ b/tests/unit/unit1307.c
@@ -43,8 +43,10 @@
 
 #define MAC_DIFFER    0x40
 #define MAC_SHIFT     16
+#if 0
 #define MAC_MATCH     ((CURL_FNMATCH_MATCH   << MAC_SHIFT) | MAC_DIFFER)
 #define MAC_NOMATCH   ((CURL_FNMATCH_NOMATCH << MAC_SHIFT) | MAC_DIFFER)
+#endif
 #define MAC_FAIL      ((CURL_FNMATCH_FAIL    << MAC_SHIFT) | MAC_DIFFER)
 
 static const char *ret2name(int i)
diff --git a/tests/unit/unit1666.c b/tests/unit/unit1666.c
index 3b8fb24158..360279501d 100644
--- a/tests/unit/unit1666.c
+++ b/tests/unit/unit1666.c
@@ -190,8 +190,6 @@ static CURLcode test_unit1666(const char *arg)
   UNITTEST_END_SIMPLE
 }
 
-#undef OID
-
 #else
 
 static CURLcode test_unit1666(const char *arg)
diff --git a/tests/unit/unit1667.c b/tests/unit/unit1667.c
index 128db099b9..6606332527 100644
--- a/tests/unit/unit1667.c
+++ b/tests/unit/unit1667.c
@@ -37,9 +37,6 @@ struct test_1667 {
   CURLcode result_exp;
 };
 
-/* the size of the object needs to deduct the null terminator */
-#define OID(x) x, sizeof(x) - 1
-
 static bool test1667(const struct test_1667 *spec, size_t i,
                      struct dynbuf *dbuf)
 {
@@ -326,8 +323,6 @@ static CURLcode test_unit1667(const char *arg)
   UNITTEST_END_SIMPLE
 }
 
-#undef OID
-
 #else
 
 static CURLcode test_unit1667(const char *arg)