[PATCH v2] Deactivate _FORTIFY_SOURCE in jitterentropy-base.c

[Hauke Mehrtens]

This fixes compilation with glibc.

_FORTIFY_SOURCE only works with compiler optimizations activated.
We have to deactivate it when we set -O0.

This fixes the following error message with glibc:
 error: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror=cpp]

musl libc does not show an error message in this case, but has the same
internal problems.

Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 CMakeLists.txt | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Changelog:
 v2: Use SET_PROPERTY and COMPILE_OPTIONS

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a1ee0c1..f415f87 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,8 +22,11 @@ ADD_EXECUTABLE(urngd
 )
 TARGET_LINK_LIBRARIES(urngd ${ubox})
 
-# jitter RNG must not be compiled with optimizations
-SET_SOURCE_FILES_PROPERTIES(${JTEN_DIR}/jitterentropy-base.c PROPERTIES COMPILE_FLAGS -O0)
+# jitter RNG must not be compiled with optimizations, _FORTIFY_SOURCE needs optimizations
+SET_PROPERTY(
+  SOURCE ${JTEN_DIR}/jitterentropy-base.c
+  APPEND PROPERTY COMPILE_OPTIONS -U_FORTIFY_SOURCE -O0
+)
 
 INSTALL(TARGETS urngd RUNTIME DESTINATION ${CMAKE_INSTALL_SBINDIR})
 
-- 
2.39.2