# Don't force apr-using projects to use the compile flags used during
# apr's compilation.
Index: apr/build/apr_rules.mk.in
===================================================================
--- apr.orig/build/apr_rules.mk.in	2010-04-21 17:20:26.000000000 +0200
+++ apr/build/apr_rules.mk.in	2013-11-01 21:22:19.655108671 +0100
@@ -41,10 +41,10 @@
 # compilation and linking flags that are supposed to be set only by the user.
 # configure adds to them for tests, but we restore them at the end.
 #
-CFLAGS=@CFLAGS@
-CPPFLAGS=@CPPFLAGS@
-LDFLAGS=@LDFLAGS@
-LIBS=@LIBS@
+CFLAGS?=@CFLAGS@
+CPPFLAGS?=@CPPFLAGS@
+LDFLAGS?=@LDFLAGS@
+LIBS?=@LIBS@
 DEFS=@DEFS@
 
 # anything added to the standard flags by configure is moved to EXTRA_*