find real compiler path during compile time

packages/nest/nest-simulator-3.6-p1-CxxRealPath.patch

+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index a924f3ebf..e369e3ed1 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -166,6 +166,11 @@ nest_process_models()
+ nest_process_with_optimize()
+ nest_process_with_debug()
+ 
++# In case the CXX compiler set is a symlink that disappears at runtime, we want
++# to resolve to the actual binary.
++# (Required e.g. for Docker build-images with Spack installations / EBRAINS Jupyter)
++file(REAL_PATH ${CMAKE_CXX_COMPILER} CMAKE_CXX_COMPILER)
++
+ nest_get_color_flags()
+ set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${NEST_C_COLOR_FLAGS}" )
+ set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${NEST_CXX_COLOR_FLAGS}" )

packages/nest/package.py

@@ -29,6 +29,7 @@ class Nest(CMakePackage):
 
     version('master', branch='master')
     version('3.6',    sha256='68d6b11791e1284dc94fef35d84c08dd7a11322c0f1e1fc9b39c5e6882284922')
+    patch('nest-simulator-3.6-p1-CxxRealPath.patch', when='@3.6')
     version('3.5',    sha256='3cdf5720854a4d8a7d359f9de9d2fb3619a0be2e36932028d6940360741547bd')
     version('3.4',    sha256='c56699111f899045ba48e55e87d14eca8763b48ebbb3648beee701a36aa3af20')
     version('3.3',    sha256='179462b966cc61f5785d2fee770bc36f86745598ace9cd97dd620622b62043ed')