[Build-System] Update configure.ac for macOS updates (#2818)

This is a request to change configure.ac  target libraries for Apple Silicon computers and a general cleanup/update for macOS.

Different target on Apple Silicon
Apple has stated that other programs should be installed into /opt for Apple Silicon computers instead of /usr/local. Homebrew installs everything in /opt. Multiple changes were made to handle this.

Added code to auto change the default from /usr/local to /opt for Apple Silicon. All other systems default to /usr/local as before.

Where target libraries were different, code was added to only add the correct libraries to the appropriate architecture. This eliminates a lot of warning message for missing libraries.

Compiler flags were updated to conform to current clang. Obsolete code that can no longer work (for old apple ancient releases or compilers) was removed or replaced.

Author: MarioG-X

configure.ac

@@ -323,10 +323,6 @@ elif test "x${ax_cv_c_compiler_vendor}" = "xclang" ; then
     esac
 elif test "x${ax_cv_c_compiler_vendor}" = "xgnu" ; then
     case "$host" in
-# older Xcode test for darwin, Xcode 4/5 use clang above
-        *darwin*)
-            SOLINK="-dynamic -bundle -force-flat-namespace"
-        ;;
         *-solaris2*)
             SOLINK="-shared -Xlinker"
         ;;
@@ -428,15 +424,6 @@ elif test "x${ax_cv_c_compiler_vendor}" = "xgnu" ; then
     fi
     if test "${enable_64}" = "yes"; then
 	case "$host" in
-             *darwin*)
-                osxvrm=`sw_vers -productVersion`          # Get version.release.modlevel
-	        osxrel=`echo $osxvrm | cut -d. -f2`       # Get release only
-                if test "$osxrel" -ge 4; then             # 10.4 and up are x64
-		   APR_ADDTO(CFLAGS, -arch x86_64)
-		   APR_ADDTO(LDFLAGS, -arch x86_64)
-		   APR_ADDTO(CXXFLAGS, -arch x86_64)
-                fi
-		;;
              *-solaris2*)
 		APR_ADDTO(CFLAGS, -m64)
 		APR_ADDTO(LDFLAGS, -m64)
@@ -653,8 +640,10 @@ path_push_unique () {
 AC_PATH_PROG([PG_CONFIG], [pg_config], [no])
 AC_PATH_PROG([PKG_CONFIG], [pkg-config], [no])
 
+# These 2 x86 libraries are not required on macOS 15 Sequoia on x86 as of June 2025. Not needed on aarch64 systems.
+# They are left here since they are likely required on older macOS systems.
 case $host in
-     *-darwin*)
+     x86_64-apple-darwin*)
 	path_push_unique PKG_CONFIG_PATH /usr/local/opt/libpq/lib/pkgconfig
 	path_push_unique PKG_CONFIG_PATH /usr/local/opt/openssl/lib/pkgconfig
      ;;
@@ -735,33 +724,33 @@ PLATFORM_CORE_LIBS=
 # tweak platform specific flags
 case "$host" in
     *darwin*)
-        # Common Apple Darwin settings
+        case "$host" in
+          aarch64-apple-darwin*)
+          # Homebrew package required libraries on Apple Silicon
+            APR_ADDTO(CPPFLAGS, -I/opt/homebrew/include)
+            APR_ADDTO(LDFLAGS, -L/opt/homebrew/lib)
+          ;;
+          *)
+          # Default package libraries on Apple x86_64
+          # The following 4 x86_64 libraries are not required on macOS 15 Sequoia as of June 2025.
+          # They are left here since they are likely required on older macOS systems.
+            APR_ADDTO(CPPFLAGS, -I/usr/local/include)  # Xcode 6 drops std lib search, add it to clang
+            APR_ADDTO(LDFLAGS,  -L/usr/local/lib)      # Xcode 6 drops std lib search, add it to clang
+            APR_ADDTO(CPPFLAGS, -I/usr/local/opt/openssl/include)
+            APR_ADDTO(LDFLAGS,  -L/usr/local/opt/openssl/lib)
+          ;;
+        esac
+       # Common Apple Clang flags
+        APR_ADDTO(CFLAGS, -pipe)
+        APR_ADDTO(LDFLAGS, -pipe)
+        APR_ADDTO(CXXFLAGS, -pipe)
+       # Common Apple Darwin settings
         APR_ADDTO(SWITCH_AM_CFLAGS, -DMACOSX)
         APR_REMOVEFROM(SWITCH_AM_CFLAGS, -fPIC)
-        APR_ADDTO(CPPFLAGS, -I/usr/local/opt/openssl/include)
-        APR_ADDTO(LDFLAGS, -L/usr/local/opt/openssl/lib)
-        APR_ADDTO(CPPFLAGS, -I/opt/homebrew/include)
-        APR_ADDTO(LDFLAGS, -L/opt/homebrew/lib)
         if test "x$enable_core_odbc_support" != "xno"; then
 	   APR_ADDTO([PLATFORM_CORE_LDFLAGS], [--framework CoreFoundation])
 	fi
 	APR_ADDTO([PLATFORM_CORE_LIBS], [-ldl])
-    # Get OSX and clang version
-        osxvrm=`sw_vers -productVersion`          # Get version.release.modlevel
-	osxrel=`echo $osxvrm | cut -d. -f2`       # Get release only
-        clangvers="`clang -v 2>&1  >/dev/null | grep version | sed -e 's/.*version \([[0-9]]*\).*$/\1/'`"
-        if test "$clangvers" -ge 6; then          # Xcode 6 drops std lib search, add it to clang
-           APR_ADDTO(LDFLAGS, -L/usr/local/lib)
-           APR_ADDTO(CPPFLAGS, -I/usr/local/include)
-        fi
-        if test "$clangvers" -ge 4; then          # Xcode 4 / 10.7 and up
-           APR_ADDTO(CFLAGS, -Wno-deprecated-declarations)
-        fi
-        if test "$osxrel" -ge 6; then             # 10.6 and up
-           APR_ADDTO(CFLAGS, -pipe -no-cpp-precomp)
-           APR_ADDTO(LDFLAGS, -pipe -bind_at_load)
-           APR_ADDTO(CXXFLAGS, -pipe)
-        fi
     ;;
     *-solaris2*)
 	if test "${enable_64}" = "yes"; then
@@ -1261,13 +1250,15 @@ GETSOUNDS="${SHELL} $switch_builddir/build/getsounds.sh"
 AC_SUBST(GETSOUNDS)
 
 case $host in
+   aarch64-apple-darwin*)
+        path_push_unique PKG_CONFIG_PATH /opt/homebrew/opt/pkgconf/
+        path_push_unique PKG_CONFIG_PATH /opt/homebrew/opt/sqlite/lib/pkgconfig/
+       ;;
    *-darwin*)
         path_push_unique PKG_CONFIG_PATH /usr/local/opt/curl/lib/pkgconfig
         path_push_unique PKG_CONFIG_PATH /usr/local/opt/sqlite/lib/pkgconfig/
         path_push_unique PKG_CONFIG_PATH /usr/local/opt/ldns/lib/pkgconfig/
         path_push_unique PKG_CONFIG_PATH /usr/local/opt/ffmpeg/lib/pkgconfig/
-        path_push_unique PKG_CONFIG_PATH /opt/homebrew/lib/pkgconfig/
-        path_push_unique PKG_CONFIG_PATH /opt/homebrew/opt/sqlite/lib/pkgconfig/
        ;;
 esac