lib: stop overriding system printf symbols

After this patch, the codebase no longer overrides system printf
functions. Instead it explicitly calls either the curl printf functions
`curl_m*printf()` or the system ones using their original names.

Also:
- drop unused `curl_printf.h` includes.
- checksrc: ban system printf functions, allow where necessary.

Follow-up to db98daab05 #18844
Follow-up to 4deea9396b #18814

Closes #18866

scripts/.checksrc

@@ -0,0 +1 @@
+allowfunc printf

scripts/Makefile.am

@@ -26,7 +26,7 @@ EXTRA_DIST = coverage.sh completion.pl firefox-db2pem.sh checksrc.pl checksrc-al
   mk-ca-bundle.pl mk-unity.pl schemetable.c cd2nroff nroff2cd cdall cd2cd managen    \
   dmaketgz maketgz release-tools.sh verify-release cmakelint.sh mdlinkcheck          \
   CMakeLists.txt perlcheck.sh pythonlint.sh randdisable wcurl top-complexity         \
-  extract-unit-protos
+  extract-unit-protos .checksrc
 
 dist_bin_SCRIPTS = wcurl
 

scripts/checksrc.pl

@@ -56,6 +56,14 @@ my %banfunc = (
     "snprintf" => 1,
     "vsprintf" => 1,
     "vsnprintf" => 1,
+    "aprintf" => 1,
+    "fprintf" => 1,
+    "msnprintf" => 1,
+    "mvsnprintf" => 1,
+    "printf" => 1,
+    "vaprintf" => 1,
+    "vfprintf" => 1,
+    "vprintf" => 1,
     "sscanf" => 1,
     "strcat" => 1,
     "strerror" => 1,