--- a/libpthread/nptl/Makefile.in
+++ b/libpthread/nptl/Makefile.in
@@ -174,7 +174,7 @@
 CFLAGS-pthread_barrierattr_setpshared.c = -D_GNU_SOURCE
 CFLAGS-sem_open.c = -D_GNU_SOURCE
 
-CFLAGS-nptl = -DNOT_IN_libc=1 -DIS_IN_libpthread=1 $(SSP_ALL_CFLAGS)
+CFLAGS-nptl = -DNOT_IN_libc=1 -DIS_IN_libpthread=1 -std=gnu99 $(SSP_ALL_CFLAGS)
 
 CFLAGS-OMIT-alloca_cutoff.c = -DNOT_IN_libc=1 -DIS_IN_libpthread=1
 CFLAGS-OMIT-forward.c = -DNOT_IN_libc=1 -DIS_IN_libpthread=1
--- a/libpthread/nptl/sysdeps/unix/sysv/linux/Makefile.in
+++ b/libpthread/nptl/sysdeps/unix/sysv/linux/Makefile.in
@@ -82,7 +82,7 @@
 CFLAGS-timer_routines.c = -I$(top_srcdir)librt -DIS_IN_librt=1
 CFLAGS-timer_settime.c = -I$(top_srcdir)librt -DIS_IN_librt=1
 
-CFLAGS-linux = -DNOT_IN_libc=1 -DIS_IN_libpthread=1 $(SSP_ALL_CFLAGS)
+CFLAGS-linux = -DNOT_IN_libc=1 -DIS_IN_libpthread=1 -std=gnu99 $(SSP_ALL_CFLAGS)
 #CFLAGS:=$(CFLAGS:-O1=-O2)
 
 CFLAGS-OMIT-libc_pthread_init.c = -DNOT_IN_libc=1 -DIS_IN_libpthread=1
--- a/ldso/ldso/Makefile.in
+++ b/ldso/ldso/Makefile.in
@@ -13,7 +13,7 @@
 CFLAGS-ldso += -fno-omit-frame-pointer
 
 CFLAGS-ldso += -I$(top_srcdir)ldso/ldso/$(TARGET_ARCH) -I$(top_srcdir)ldso/include -I$(top_srcdir)ldso/ldso
-CFLAGS-ldso += -DUCLIBC_RUNTIME_PREFIX=\"$(RUNTIME_PREFIX)\" -DUCLIBC_LDSO=\"$(UCLIBC_LDSO)\"
+CFLAGS-ldso += -DUCLIBC_RUNTIME_PREFIX=\"$(RUNTIME_PREFIX)\" -DUCLIBC_LDSO=\"$(UCLIBC_LDSO)\" -std=gnu99
 
 ifeq ($(DODEBUG),y)
 # Not really much point in including debugging info, since gdb
