From 7aad159464b3a31a42789594e6efd4bd2fceb644 Mon Sep 17 00:00:00 2001
From: Renato Westphal <renato@opensourcerouting.org>
Date: Sat, 2 Jun 2018 22:00:32 -0300
Subject: [PATCH] build: append -std=gnu99 after SNMP_CFLAGS

Programs that link to libnetsnmp must be compiled using a special set
of flags as specified by the "net-snmp-config --base-cflags" command
(whose output is stored in the SNMP_CFLAGS variable). The problem is
that "net-snmp-config --base-cflags" can output -std=c99 in addition to
other compiler flags in some platforms, and this breaks the build since
FRR souce code makes use of some GNU compiler extensions (e.g. allow
trailing commas in function parameter lists). In order to solve this
problem, append -std=gnu99 after SNMP_CFLAGS in all makefiles where this
variable is used. This way the -std=c99 flag will be overwritten when it's
present. Source files that don't link to libnetsnmp will be compiled using
either -std=gnu99 or -std=gnu11 depending on the compiler availability.

Fixes #1617.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
---
 bgpd/Makefile.am | 2 +-
 lib/subdir.am    | 2 +-
 ospf6d/subdir.am | 2 +-
 ospfd/subdir.am  | 2 +-
 ripd/subdir.am   | 2 +-
 zebra/subdir.am  | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/bgpd/Makefile.am b/bgpd/Makefile.am
index 8a410adca1..6761389100 100644
--- a/bgpd/Makefile.am
+++ b/bgpd/Makefile.am
@@ -116,7 +116,7 @@ module_LTLIBRARIES += bgpd_snmp.la
 endif
 
 bgpd_snmp_la_SOURCES = bgp_snmp.c
-bgpd_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS)
+bgpd_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS) -std=gnu99
 bgpd_snmp_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 bgpd_snmp_la_LIBADD = ../lib/libfrrsnmp.la
 
diff --git a/lib/subdir.am b/lib/subdir.am
index c5719786d6..1c3d31b927 100644
--- a/lib/subdir.am
+++ b/lib/subdir.am
@@ -190,7 +190,7 @@ if SNMP
 lib_LTLIBRARIES += lib/libfrrsnmp.la
 endif
 
-lib_libfrrsnmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS)
+lib_libfrrsnmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS) -std=gnu99
 lib_libfrrsnmp_la_LDFLAGS = -version-info 0:0:0
 lib_libfrrsnmp_la_LIBADD = lib/libfrr.la $(SNMP_LIBS)
 lib_libfrrsnmp_la_SOURCES = \
diff --git a/ospf6d/subdir.am b/ospf6d/subdir.am
index 76a64cd637..8a6c4a5ccf 100644
--- a/ospf6d/subdir.am
+++ b/ospf6d/subdir.am
@@ -61,6 +61,6 @@ ospf6d_ospf6d_SOURCES = \
 	# end
 
 ospf6d_ospf6d_snmp_la_SOURCES = ospf6d/ospf6_snmp.c
-ospf6d_ospf6d_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS)
+ospf6d_ospf6d_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS) -std=gnu99
 ospf6d_ospf6d_snmp_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 ospf6d_ospf6d_snmp_la_LIBADD = lib/libfrrsnmp.la
diff --git a/ospfd/subdir.am b/ospfd/subdir.am
index 9f04260366..f2e292e186 100644
--- a/ospfd/subdir.am
+++ b/ospfd/subdir.am
@@ -89,7 +89,7 @@ ospfd_ospfd_LDADD = ospfd/libfrrospf.a lib/libfrr.la @LIBCAP@ @LIBM@
 ospfd_ospfd_SOURCES = ospfd/ospf_main.c
 
 ospfd_ospfd_snmp_la_SOURCES = ospfd/ospf_snmp.c
-ospfd_ospfd_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS)
+ospfd_ospfd_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS) -std=gnu99
 ospfd_ospfd_snmp_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 ospfd_ospfd_snmp_la_LIBADD = lib/libfrrsnmp.la
 
diff --git a/ripd/subdir.am b/ripd/subdir.am
index 7a8f2185ba..1c5167ef4a 100644
--- a/ripd/subdir.am
+++ b/ripd/subdir.am
@@ -35,7 +35,7 @@ ripd_ripd_SOURCES = \
 	# end
 
 ripd_ripd_snmp_la_SOURCES = ripd/rip_snmp.c
-ripd_ripd_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS)
+ripd_ripd_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS) -std=gnu99
 ripd_ripd_snmp_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 ripd_ripd_snmp_la_LIBADD = lib/libfrrsnmp.la
 
diff --git a/zebra/subdir.am b/zebra/subdir.am
index 45e285a9e7..d3abcef6d5 100644
--- a/zebra/subdir.am
+++ b/zebra/subdir.am
@@ -127,7 +127,7 @@ zebra_zebra_irdp_la_SOURCES = \
 zebra_zebra_irdp_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 
 zebra_zebra_snmp_la_SOURCES = zebra/zebra_snmp.c
-zebra_zebra_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS)
+zebra_zebra_snmp_la_CFLAGS = $(WERROR) $(SNMP_CFLAGS) -std=gnu99
 zebra_zebra_snmp_la_LDFLAGS = -avoid-version -module -shared -export-dynamic
 zebra_zebra_snmp_la_LIBADD = lib/libfrrsnmp.la
 
-- 
2.39.5