move to new cspot

components/spotify/cspot/bell/external/opus/cmake/CFeatureCheck.cmake

@@ -0,0 +1,39 @@
+# - Compile and run code to check for C features
+#
+# This functions compiles a source file under the `cmake` folder
+# and adds the corresponding `HAVE_[FILENAME]` flag to the CMake
+# environment
+#
+#  c_feature_check(<FLAG> [<VARIANT>])
+#
+# - Example
+#
+# include(CFeatureCheck)
+# c_feature_check(VLA)
+
+if(__c_feature_check)
+  return()
+endif()
+set(__c_feature_check INCLUDED)
+
+function(c_feature_check FILE)
+  string(TOLOWER ${FILE} FILE)
+  string(TOUPPER ${FILE} VAR)
+  string(TOUPPER "${VAR}_SUPPORTED" FEATURE)
+  if (DEFINED ${VAR}_SUPPORTED)
+    set(${VAR}_SUPPORTED 1 PARENT_SCOPE)
+    return()
+  endif()
+
+  if (NOT DEFINED COMPILE_${FEATURE})
+      message(STATUS "Performing Test ${FEATURE}")
+      try_compile(COMPILE_${FEATURE} ${PROJECT_BINARY_DIR} ${PROJECT_SOURCE_DIR}/cmake/${FILE}.c)
+  endif()
+
+  if(COMPILE_${FEATURE})
+    message(STATUS "Performing Test ${FEATURE} -- success")
+    set(${VAR}_SUPPORTED 1 PARENT_SCOPE)
+  else()
+    message(STATUS "Performing Test ${FEATURE} -- failed to compile")
+  endif()
+endfunction()