lower gcc minver to 9 to enable building on Ubuntu 20 LTS

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3485e5f8d414dc117d1c4d3e37fecd4146d39be2..76bca8134d4a4457375b77c11b020d6d83eb0107 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -259,7 +259,7 @@ set(ARCH_CXX_FLAGS "-${ARCH_FLAG}=${GNUCC_ARCH} -mtune=${TUNE_FLAG} ${ARCH_CXX_F
 
 # compiler version checks TODO: test more compilers
 if (CMAKE_COMPILER_IS_GNUCXX)
-    set(GNUCXX_MINVER "10")
+    set(GNUCXX_MINVER "9")
     message(STATUS "g++ version ${CMAKE_CXX_COMPILER_VERSION}")
     if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS GNUCXX_MINVER)
         message(FATAL_ERROR "A minimum of g++ ${GNUCXX_MINVER} is required for C++17 support")