Don't override the user's compiler choice.
https://github.com/irstlm-team/irstlm/pull/26
--- CMakeLists.txt.orig	2015-12-09 17:31:15.000000000 -0600
+++ CMakeLists.txt	2023-02-05 17:54:25.000000000 -0600
@@ -9,4 +9,2 @@
 
-SET(CMAKE_C_COMPILER "gcc" )
-SET(CMAKE_CXX_COMPILER "g++" )