Fix parsing of -s settings when one refers to a value that has an equals sign in it. Fixes #5467.

Author: juj

emcc.py

@@ -861,7 +861,7 @@ def check(input_file):
 
       # Apply -s settings in newargs here (after optimization levels, so they can override them)
       for change in settings_changes:
-        key, value = change.split('=')
+        key, value = change.split('=', 1)
 
         # In those settings fields that represent amount of memory, translate suffixes to multiples of 1024.
         if key in ['TOTAL_STACK', 'TOTAL_MEMORY', 'GL_MAX_TEMP_BUFFER_SIZE', 'SPLIT_MEMORY', 'BINARYEN_MEM_MAX']: