commit 9fcdd6fc25fcb232038355c6103eb6f06bcd5dd5
author Eric Fiselier <eric@efcs.ca> Mon May 23 20:51:15 2016 -0600
committer Eric Fiselier <eric@efcs.ca> Mon May 23 20:51:15 2016 -0600
tree 48ec00ede31fad722c7859b2b608a7b633f9acdf
parent c7108df977c40c7794701c369a8cb66135d75e14

Prevent re-execution of slow feature tests.

cmake/CXXFeatureCheck.cmake

diff --git a/cmake/CXXFeatureCheck.cmake b/cmake/CXXFeatureCheck.cmake
index 23ee8ac..3059024 100644
--- a/cmake/CXXFeatureCheck.cmake
+++ b/cmake/CXXFeatureCheck.cmake
@@ -21,12 +21,15 @@
   string(TOLOWER ${FILE} FILE)
   string(TOUPPER ${FILE} VAR)
   string(TOUPPER "HAVE_${VAR}" FEATURE)
+  if (DEFINED HAVE_${VAR})
+    return()
+  endif()
   message("-- Performing Test ${FEATURE}")
   try_run(RUN_${FEATURE} COMPILE_${FEATURE}
           ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/${FILE}.cpp)
   if(RUN_${FEATURE} EQUAL 0)
     message("-- Performing Test ${FEATURE} -- success")
-    set(HAVE_${VAR} 1 PARENT_SCOPE)
+    set(HAVE_${VAR} 1 CACHE INTERNAL "Feature test for ${FILE}" PARENT_SCOPE)
     add_definitions(-DHAVE_${VAR})
   else()
     if(NOT COMPILE_${FEATURE})