On macOS, use -isysroot in link steps as well as compile steps.

tglsfdc · tglsfdc · commit 2bb8c0f1d94d · 2020-11-20T00:58:26.000-05:00
We previously put the -isysroot switch only into CPPFLAGS, theorizing that it was only needed to find the right copies of include files. However, it seems that we also need to use it while linking programs, to find the right stub ".tbd" files for libraries. We got away without that up to now, but apparently that was mostly luck. It may also be that failures are only observed when the Xcode version is noticeably out of sync with the host macOS version; the case that's prompting action right now is that builds fail when using latest Xcode (12.2) on macOS Catalina, even though it's fine on Big Sur. Hence, add -isysroot to LDFLAGS as well. (It seems that the more common practice is to put it in CFLAGS, whence it'd be included at both compile and link steps. However, we can't mess with CFLAGS in the platform template file without confusing configure's logic for choosing default CFLAGS.) Back-patch of 49407dc into all supported branches. Report and patch by James Hilliard (some cosmetic mods by me) Discussion: https://postgr.es/m/20201120003314.20560-1-james.hilliard1@gmail.com
diff --git a/configure b/configure
@@ -16285,8 +16285,10 @@ _ACEOF
 # literally, so that it's possible to override it at build time using
 # a command like "make ... PG_SYSROOT=path".  This has to be done after
 # we've finished all configure checks that depend on CPPFLAGS.
+# The same for LDFLAGS, too.
 if test x"$PG_SYSROOT" != x; then
   CPPFLAGS=`echo "$CPPFLAGS" | sed -e "s| $PG_SYSROOT | \\\$(PG_SYSROOT) |"`
+  LDFLAGS=`echo "$LDFLAGS" | sed -e "s| $PG_SYSROOT | \\\$(PG_SYSROOT) |"`
 fi
 
 
diff --git a/configure.in b/configure.in
@@ -2227,8 +2227,10 @@ AC_SUBST(PG_VERSION_NUM)
 # literally, so that it's possible to override it at build time using
 # a command like "make ... PG_SYSROOT=path".  This has to be done after
 # we've finished all configure checks that depend on CPPFLAGS.
+# The same for LDFLAGS, too.
 if test x"$PG_SYSROOT" != x; then
   CPPFLAGS=`echo "$CPPFLAGS" | sed -e "s| $PG_SYSROOT | \\\$(PG_SYSROOT) |"`
+  LDFLAGS=`echo "$LDFLAGS" | sed -e "s| $PG_SYSROOT | \\\$(PG_SYSROOT) |"`
 fi
 AC_SUBST(PG_SYSROOT)
 
diff --git a/src/template/darwin b/src/template/darwin
@@ -11,6 +11,7 @@ fi
 if test x"$PG_SYSROOT" != x"" ; then
   if test -d "$PG_SYSROOT" ; then
     CPPFLAGS="-isysroot $PG_SYSROOT $CPPFLAGS"
+    LDFLAGS="-isysroot $PG_SYSROOT $LDFLAGS"
   else
     PG_SYSROOT=""
   fi
