Fixed issues 2496. Used option 4: parse_version.cmake to avoid python3 usage.
https://github.com/KhronosGroup/glslang/issues/2496
diff --git a/parse_version.cmake b/parse_version.cmake
new file mode 100644
index 0000000..b826096
--- /dev/null
+++ b/parse_version.cmake
@@ -0,0 +1,41 @@
+# Copyright 2020 The Marl Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# parse_version() reads and parses the version string from FILE, assigning the
+# version string to ${PROJECT}_VERSION and the parsed version to
+# ${PROJECT}_VERSION_MAJOR, ${PROJECT}_VERSION_MINOR, ${PROJECT}_VERSION_PATCH,
+# and the optional ${PROJECT}_VERSION_FLAVOR.
+#
+# The version string take one of the forms:
+# <major>.<minor>.<patch>
+# <major>.<minor>.<patch>-<flavor>
+function(parse_version FILE PROJECT)
+ configure_file(${FILE} "${CMAKE_CURRENT_BINARY_DIR}/CHANGES.md") # Required to re-run cmake on version change
+ file(READ ${FILE} CHANGES)
+ if(${CHANGES} MATCHES "#+ *([0-9]+)\\.([0-9]+)\\.([0-9]+)(-[a-zA-Z0-9]+)?")
+ set(FLAVOR "")
+ if(NOT "${CMAKE_MATCH_4}" STREQUAL "")
+ string(SUBSTRING ${CMAKE_MATCH_4} 1 -1 FLAVOR)
+ endif()
+ set("${PROJECT}_VERSION_MAJOR" ${CMAKE_MATCH_1} PARENT_SCOPE)
+ set("${PROJECT}_VERSION_MINOR" ${CMAKE_MATCH_2} PARENT_SCOPE)
+ set("${PROJECT}_VERSION_PATCH" ${CMAKE_MATCH_3} PARENT_SCOPE)
+ set("${PROJECT}_VERSION_FLAVOR" ${FLAVOR} PARENT_SCOPE)
+ set("${PROJECT}_VERSION"
+ "${CMAKE_MATCH_1}.${CMAKE_MATCH_2}.${CMAKE_MATCH_3}${CMAKE_MATCH_4}"
+ PARENT_SCOPE)
+ else()
+ message(FATAL_ERROR "Unable to parse version from '${FILE}'")
+ endif()
+endfunction()