diff --git a/Makeconfig b/Makeconfig
index bbe83ec..69ecb43 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -884,7 +884,7 @@ CPPFLAGS = $(config-extra-cppflags) $(CPPUNDEFS) $(CPPFLAGS-config) \
 	   $(foreach lib,$(libof-$(basename $(@F))) \
 			 $(libof-$(<F)) $(libof-$(@F)),$(CPPFLAGS-$(lib))) \
 	   $(CPPFLAGS-$(<F)) $(CPPFLAGS-$(@F)) $(CPPFLAGS-$(basename $(@F)))
-override CFLAGS	= -std=gnu99 $(gnu89-inline-CFLAGS) $(config-extra-cflags) \
+override CFLAGS	= -std=gnu11 $(gnu89-inline-CFLAGS) $(config-extra-cflags) \
 		  $(filter-out %frame-pointer,$(+cflags)) $(+gccwarn-c) \
 		  $(sysdep-CFLAGS) $(CFLAGS-$(suffix $@)) $(CFLAGS-$(<F)) \
 		  $(CFLAGS-$(@F)) $(tls-model) \
diff --git a/Makefile b/Makefile
index a2abfb9..c3227aa 100644
--- a/Makefile
+++ b/Makefile
@@ -256,7 +256,7 @@ ifneq ($(CXX),no)
 vpath c++-types.data $(+sysdep_dirs)
 
 $(objpfx)c++-types-check.out: c++-types.data scripts/check-c++-types.sh
-	scripts/check-c++-types.sh $< $(CXX) $(filter-out -std=gnu99 -Wstrict-prototypes,$(CFLAGS)) $(CPPFLAGS) > $@; \
+	scripts/check-c++-types.sh $< $(CXX) $(filter-out -std=gnu11 -Wstrict-prototypes,$(CFLAGS)) $(CPPFLAGS) > $@; \
 	$(evaluate-test)
 endif
 
diff --git a/configure b/configure
index c5510f6..5d9b87c 100755
--- a/configure
+++ b/configure
@@ -3789,7 +3789,7 @@ if ${libc_cv_sdt+:} false; then :
   $as_echo_n "(cached) " >&6
 else
     old_CFLAGS="$CFLAGS"
-  CFLAGS="-std=gnu99 $CFLAGS"
+  CFLAGS="-std=gnu11 $CFLAGS"
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <sys/sdt.h>
@@ -6432,7 +6432,7 @@ main () { return 0;}
 #error
 #endif
 EOF
-if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -S -std=gnu99 -fgnu89-inline
+if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -S -std=gnu11 -fgnu89-inline
 			    -o conftest.s conftest.c 1>&5'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
diff --git a/configure.ac b/configure.ac
index ea89b3b..75c1fc1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -336,7 +336,7 @@ AC_ARG_ENABLE([systemtap],
 if test "x$systemtap" != xno; then
   AC_CACHE_CHECK([for systemtap static probe support], libc_cv_sdt, [dnl
   old_CFLAGS="$CFLAGS"
-  CFLAGS="-std=gnu99 $CFLAGS"
+  CFLAGS="-std=gnu11 $CFLAGS"
   AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#include <sys/sdt.h>
 void foo (int i, void *p)
 {
@@ -1587,7 +1587,7 @@ main () { return 0;}
 #error
 #endif
 EOF
-if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -std=gnu99 -fgnu89-inline
+if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -std=gnu11 -fgnu89-inline
 			    -o conftest.s conftest.c 1>&AS_MESSAGE_LOG_FD])
 then
   libc_cv_gnu89_inline=yes
diff --git a/math/gen-auto-libm-tests.c b/math/gen-auto-libm-tests.c
index 465f7c6..3fa4597 100644
--- a/math/gen-auto-libm-tests.c
+++ b/math/gen-auto-libm-tests.c
@@ -18,7 +18,7 @@
 
 /* Compile this program as:
 
-   gcc -std=gnu99 -O2 -Wall -Wextra gen-auto-libm-tests.c -lmpc -lmpfr -lgmp \
+   gcc -std=gnu11 -O2 -Wall -Wextra gen-auto-libm-tests.c -lmpc -lmpfr -lgmp \
      -o gen-auto-libm-tests
 
    (use of current MPC and MPFR versions recommended) and run it as: