[cmake] Clarify variable usage through its name.

Author: ChrisCummins

CMakeLists.txt

@@ -44,13 +44,14 @@ include(build_tools/cmake/cg_filegroup.cmake)
 include(build_tools/cmake/grpc.cmake)
 include(build_tools/cmake/protobuf.cmake)
 
-set(COMPILER_GYM_PYTHONPATH "$ENV{PYTHONPATH}"
+# Set up the build Python path.
+set(COMPILER_GYM_BUILD_PYTHONPATH "$ENV{PYTHONPATH}"
     CACHE STRING "PYTHONPATH environment variable during build step."
 )
-if(COMPILER_GYM_PYTHONPATH)
-    string(PREPEND COMPILER_GYM_PYTHONPATH ":")
+if(COMPILER_GYM_BUILD_PYTHONPATH)
+    string(PREPEND COMPILER_GYM_BUILD_PYTHONPATH ":")
 endif()
-string(PREPEND COMPILER_GYM_PYTHONPATH "${CMAKE_BINARY_DIR}")
+string(PREPEND COMPILER_GYM_BUILD_PYTHONPATH "${CMAKE_BINARY_DIR}")
 include(build_tools/cmake/set_command_pythonpath.cmake)
 
 set(DEFAULT_CMAKE_BUILD_TYPE "Release")

build_tools/cmake/set_command_pythonpath.cmake

@@ -2,15 +2,14 @@
 #
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
-
 include(CMakeParseArguments)
 
 function(set_command_pythonpath)
     cmake_parse_arguments(_ARG "" "COMMAND;RESULT" "" ${ARGN})
 
-    if(COMPILER_GYM_PYTHONPATH)
+    if(COMPILER_GYM_BUILD_PYTHONPATH)
         set(${_ARG_RESULT}
-            "\"${CMAKE_COMMAND}\" -E env \"PYTHONPATH=${COMPILER_GYM_PYTHONPATH}\" ${_ARG_COMMAND}"
+            "\"${CMAKE_COMMAND}\" -E env \"PYTHONPATH=${COMPILER_GYM_BUILD_PYTHONPATH}\" ${_ARG_COMMAND}"
             PARENT_SCOPE
         )
     else()