Remove code that looks for default Fink and MacPorts prefixes.
Patch in a placeholder for the applications directory which will be replaced
with the real value by the Portfile.

https://github.com/gpac/gpac/pull/2822
--- configure	2026-02-05 21:26:28.000000000 +0800
+++ configure	2026-05-10 07:46:14.000000000 +0800
@@ -993,20 +993,8 @@
             LDFLAGS="$LDFLAGS -L$prefix/$libdir"
         fi
 
-        if test "$is_em" != "yes" ; then
-            if test -d /sw/bin ; then
-                alt_macosx_dir="/sw"
-            elif test -d /opt/local/bin ; then
-                alt_macosx_dir="/opt/local"
-            fi
-            if test "$alt_macosx_dir" != "" ; then
-                CFLAGS_DIR="$CFLAGS_DIR -I$alt_macosx_dir -I$alt_macosx_dir/include"
-                LDFLAGS="$LDFLAGS -L$alt_macosx_dir -L$alt_macosx_dir/lib"
-            fi
-        fi
-
         CFLAGS="$CFLAGS_DIR $CFLAGS"
-        Mac_Applications="/Applications"
+        Mac_Applications="@APPLICATIONS_DIR@"
         SHFLAGS="-dynamiclib"
         DYN_LIB_SUFFIX=".dylib"
         extralibs=""