commit 2f26bf7e886a091003016427ec52d74848d84c88
author Gilles Peskine <gilles.peskine@arm.com> Mon Oct 05 17:25:29 2020 +0200
committer GitHub <noreply@github.com> Mon Oct 05 17:25:29 2020 +0200
tree 03cdf06c454dc4597b1fc942189db1d2ea4a6eeb
parent 188e192eeb85d68ae0281100affe0c31c74abcb9
parent 90b545881c0964ea006c7eded746487205c31af3

Merge pull request #3735 from gilles-peskine-arm/entropy_poll-_gnu_source-2.16

Backport 2.16: Don't redefine _GNU_SOURCE if it's already defined

ChangeLog.d/_GNU_SOURCE-redefined.txt

diff --git a/ChangeLog.d/_GNU_SOURCE-redefined.txt b/ChangeLog.d/_GNU_SOURCE-redefined.txt
new file mode 100644
index 0000000..59c8a15
--- /dev/null
+++ b/ChangeLog.d/_GNU_SOURCE-redefined.txt
@@ -0,0 +1,3 @@
+Bugfix
+   * Fix the build when the macro _GNU_SOURCE is defined to a non-empty value.
+     Fix #3432.

library/entropy_poll.c

diff --git a/library/entropy_poll.c b/library/entropy_poll.c
index 4ad878e..d7062ea 100644
--- a/library/entropy_poll.c
+++ b/library/entropy_poll.c
@@ -44,7 +44,7 @@
  *  **********
  */
 
-#if defined(__linux__)
+#if defined(__linux__) && !defined(_GNU_SOURCE)
 /* Ensure that syscall() is available even when compiling with -std=c99 */
 #define _GNU_SOURCE
 #endif