GHA: tidy up parallel options, improve performance for some jobs

- replace `--parallel <n>` and `-j<n>` for individual commands with
  `MAKEFLAGS`, for jobs not yet doing it.
  This enables parallel builds in distcheck / maketgz-and-verify-in-tree,
  where `-j` option was missing.
- add `--parallel` for iOS Xcode job for improved performance.
- drop redundant `-j5` for Android jobs.
- drop stray `cmake --config` options from single-target jobs (cygwin,
  msys/mingw, dl-mingw, non-native). Drop redundant
  `CMAKE_RUNTIME_OUTPUT_DIRECTORY_*` settings too.
- GHA/windows: add timeout for package install steps where missing.
- GHA/non-native: specify target type explicitly for iOS cmake jobs.
  Xcode default was already Debug, single-target default was generic,
  now it's Release, with unity batch to keep it fast.

`MAKEFLAGS` is necessary for autotools jobs and CMake jobs using
the default (GNU Make) generator. It's ignored by Ninja and other tools.
`cmake --parallel` is still necessary for jobs with Visual Studio or
Xcode generators. Parallelism is 5 for GHA Linux and Windows runners,
4 for macOS, 3 for VMs, 2 for AppVeyor.

Closes #16502

.github/workflows/distcheck.yml

@@ -19,6 +19,9 @@ concurrency:
 
 permissions: {}
 
+env:
+  MAKEFLAGS: -j 5
+
 jobs:
   maketgz-and-verify-in-tree:
     runs-on: ubuntu-latest
@@ -55,9 +58,9 @@ jobs:
           tar xvf curl-99.98.97.tar.gz
           pushd curl-99.98.97
           ./configure --prefix=$HOME/temp --without-ssl --without-libpsl
-          make -j5
-          make -j5 test-ci
-          make -j5 install
+          make
+          make test-ci
+          make install
           popd
           # basic check of the installed files
           bash scripts/installcheck.sh $HOME/temp
@@ -80,8 +83,8 @@ jobs:
           mkdir build
           pushd build
           ../curl-99.98.97/configure --without-ssl --without-libpsl
-          make -j5
-          make -j5 test-ci
+          make
+          make test-ci
           popd
           rm -rf build
           rm -rf curl-99.98.97
@@ -103,9 +106,9 @@ jobs:
           mkdir build
           pushd build
           ../configure --without-ssl --enable-debug "--prefix=${PWD}/pkg" --without-libpsl
-          make -j5
-          make -j5 test-ci
-          make -j5 install
+          make
+          make test-ci
+          make install
 
   verify-out-of-tree-cmake:
     runs-on: ubuntu-latest
@@ -122,7 +125,7 @@ jobs:
           tar xvf curl-99.98.97.tar.gz
           pushd curl-99.98.97
           cmake -B build -DCURL_WERROR=ON -DCURL_USE_LIBPSL=OFF
-          make -C build -j5
+          make -C build
 
   missing-files:
     runs-on: ubuntu-latest