[PATCH] Fix build of jitterentropy-base.c with clang

[Tom Stellard]

Clang has a slightly different pragma to disable optimizations.
---
 random/jitterentropy-base.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/random/jitterentropy-base.c b/random/jitterentropy-base.c
index 32fdea46..2c198ef5 100644
--- a/random/jitterentropy-base.c
+++ b/random/jitterentropy-base.c
@@ -50,6 +50,14 @@
  */
 
 #undef _FORTIFY_SOURCE
+#ifdef __clang__
+#pragma clang optimize off
+
+/* clang does not undefine the __OPTIMIZE__ macro after using the
+ * clang optimize off pragma, so the same __OPTIMIZE__ check below that
+ * is used for gcc won't work.
+ */
+#else
 #pragma GCC optimize ("O0")
 
 #include "jitterentropy.h"
@@ -60,6 +68,7 @@
   #error "The CPU Jitter random number generator must not be compiled with optimizations. See documentation. Use the compiler switch -O0 for compiling jitterentropy-base.c."
  #endif
 #endif
+#endif
 
 #define MAJVERSION 2 /* API / ABI incompatible changes, functional changes that
 		      * require consumer to be updated (as long as this number
-- 
2.26.2