Let Linux makefile inherit CFLAGS/CFLAGS_DYNAMIC.

Pulled from Debian 30_dontoverridecflags.dpatch by Andreas Metzler.
We just add CFLAGS_DYNAMIC too and some comments.

Non-POSIX syntax, but fairly portable; GNU make gained it in 1998,
we believe even very old systems should handle it fine.

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 8fa9621bd562d28a6c942ec5a7dac07a8e95577e..d1beab6e025f57558bbf36093b8ef1e9b0c64275 100644 (file)
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -46,6 +46,9 @@ JH/03 Add expansion operators ${listnamed:name} and ${listcount:string}
 
 PP/09 Add gnutls_enable_pkcs11 option.
 
+PP/10 Let Linux makefile inherit CFLAGS/CFLAGS_DYNAMIC.
+      Pulled from Debian 30_dontoverridecflags.dpatch by Andreas Metzler.
+
 
 Exim version 4.80
 -----------------

diff --git a/src/OS/Makefile-Linux b/src/OS/Makefile-Linux
index 8b721410e7b11a96a5206a75fe2059d8898abd18..990f884e9cb2b33ac3ce734986c461312b21449e 100644 (file)
--- a/src/OS/Makefile-Linux
+++ b/src/OS/Makefile-Linux
@@ -1,5 +1,9 @@
 # Exim: OS-specific make file for Linux. This is for modern Linuxes,
 # which use libc6.
+#
+# For Linux, we assume GNU Make; at time of writing, the only extension
+# used is ?= which is actually portable to other maintained Make variants,
+# just is not POSIX.
 
 HAVE_ICONV=yes
 
@@ -8,8 +12,9 @@ CHOWN_COMMAND=look_for_it
 CHGRP_COMMAND=look_for_it
 CHMOD_COMMAND=look_for_it
 
-CFLAGS=-O -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
-CFLAGS_DYNAMIC=-shared -rdynamic
+# Preserve CFLAGS and CFLAGS_DYNAMIC from the caller/environment
+CFLAGS ?= -O -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
+CFLAGS_DYNAMIC ?= -shared -rdynamic
 
 DBMLIB = -ldb
 USE_DB = yes