Autotools: Use FPM_EXTRA_LIBS for apparmor library

Instead of appending -lapparmor to global LIBS variable, this adds it as
needed only to FPM_EXTRA_LIBS as it was already used in the BUILD_FPM
invocation.

Follow-up of GH-14881

Author: petk

sapi/fpm/config.m4

@@ -436,7 +436,8 @@ if test "$PHP_FPM" != "no"; then
     [no],
     [no])
 
-  PHP_ARG_WITH([fpm-apparmor],,
+  PHP_ARG_WITH([fpm-apparmor],
+    [whether to enable AppArmor confinement in PHP-FPM],
     [AS_HELP_STRING([--with-fpm-apparmor],
       [Support AppArmor confinement through libapparmor])],
     [no],
@@ -493,23 +494,27 @@ if test "$PHP_FPM" != "no"; then
     ])
   fi
 
-  if test "x$PHP_FPM_APPARMOR" != "xno" ; then
+  AS_VAR_IF([PHP_FPM_APPARMOR], [no],, [
+    ext_shared_save=$ext_shared
+    ext_shared=yes
     PKG_CHECK_MODULES([APPARMOR], [libapparmor], [
-      PHP_EVAL_LIBLINE([$APPARMOR_LIBS])
+      PHP_EVAL_LIBLINE([$APPARMOR_LIBS], [FPM_EXTRA_LIBS])
       PHP_EVAL_INCLINE([$APPARMOR_CFLAGS])
     ],
       [AC_CHECK_LIB([apparmor], [aa_change_profile],
         [PHP_ADD_LIBRARY([apparmor])],
         [AC_MSG_ERROR([libapparmor required but not found.])])])
+    ext_shared=$ext_shared_save
 
     dnl Sanity check.
-    CFLAGS_save="$CFLAGS"
+    CFLAGS_save=$CFLAGS
     CFLAGS="$INCLUDES $CFLAGS"
     AC_CHECK_HEADER([sys/apparmor.h],
-      [AC_DEFINE([HAVE_APPARMOR], [1], [AppArmor confinement available])],
+      [AC_DEFINE([HAVE_APPARMOR], [1],
+        [Define to 1 if AppArmor confinement is available for PHP-FPM.])],
       [AC_MSG_ERROR([Required sys/apparmor.h not found.])])
-    CFLAGS="$CFLAGS_save"
-  fi
+    CFLAGS=$CFLAGS_save
+  ])
 
   if test "x$PHP_FPM_SELINUX" != "xno" ; then
     PKG_CHECK_MODULES([SELINUX], [libselinux], [
@@ -611,4 +616,5 @@ if test "$PHP_FPM" != "no"; then
 
   PHP_SUBST([SAPI_FPM_PATH])
   PHP_SUBST([BUILD_FPM])
+  PHP_SUBST([FPM_EXTRA_LIBS])
 fi