commit a0126e96eba430580b4bb2e4ff9e63dfd93751f1
author James Zern <jzern@google.com> Fri Aug 26 15:47:52 2022 -0700
committer James Zern <jzern@google.com> Sat Aug 27 02:14:08 2022 +0000
tree 2eeb0bdaa32b3a3de76925bc1fefe54c0930b2d0
parent 44b2702c065db1f0a799e931f2853f7a1cb1ea9f

cmake: fix gcc 10+ -Wextra-semi detection w/cmake < 3.19

Prior to version 3.19.0 cmake would fail to parse the warning emitted by
gcc with this flag. This avoids:
  cc1: warning: command-line option '-Wextra-semi' is valid for
  C++/ObjC++ but not for C

https://gitlab.kitware.com/cmake/cmake/-/issues/21275

Change-Id: I976fcf21298f7265337d5ed25f666ad73d259722

build/cmake/aom_configure.cmake

diff --git a/build/cmake/aom_configure.cmake b/build/cmake/aom_configure.cmake
index 7a95cba..005c87f 100644
--- a/build/cmake/aom_configure.cmake
+++ b/build/cmake/aom_configure.cmake
@@ -300,7 +300,17 @@
   add_compiler_flag_if_supported("-Wall")
   add_compiler_flag_if_supported("-Wdisabled-optimization")
   add_compiler_flag_if_supported("-Wextra")
-  add_compiler_flag_if_supported("-Wextra-semi")
+  # Prior to version 3.19.0 cmake would fail to parse the warning emitted by gcc
+  # with this flag. Note the order of this check and -Wextra-semi-stmt is
+  # important due to is_flag_present() matching substrings with string(FIND
+  # ...).
+  if(CMAKE_VERSION VERSION_LESS "3.19"
+     AND CMAKE_C_COMPILER_ID STREQUAL "GNU"
+     AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10)
+    add_cxx_flag_if_supported("-Wextra-semi")
+  else()
+    add_compiler_flag_if_supported("-Wextra-semi")
+  endif()
   add_compiler_flag_if_supported("-Wextra-semi-stmt")
   add_compiler_flag_if_supported("-Wfloat-conversion")
   add_compiler_flag_if_supported("-Wformat=2")