Avoid hardcoded python binary path (#320)

* Avoid hardcoded python binary path
* Find python interpreter

fixes #319

Author: pramodk

CMakeLists.txt

@@ -86,6 +86,11 @@ endif()
 include(OpenAccHelper)
 include(ClangFormatHelper)
 
+# =============================================================================
+# Common dependencies
+# =============================================================================
+find_package(PythonInterp REQUIRED)
+
 # =============================================================================
 # ISPC should compile with --pic by default
 # =============================================================================

extra/nrnivmodl_core_makefile.in

@@ -190,7 +190,7 @@ $(kinderiv_h): $(mod_all_cpp_files) build_always | $(MODC_DIR)
 	cd $(MODC_DIR) && mkdir -p _tmp &&	mv [^_]*.cpp _tmp/ && \
 	  mv $(addprefix _tmp/,$(notdir $(mod_all_cpp_files))) ./ || true
 	rm -rf $(MODC_DIR)/_tmp
-	cd $(MODC_DIR) && python $(datadir)/kinderiv.py
+	cd $(MODC_DIR) && @PYTHON_EXECUTABLE@ $(datadir)/kinderiv.py
 
 
 $(dimplic_c): $(dimplic_src) | $(MODC_DIR)