diff --git a/src/glsl/SConscript b/src/glsl/SConscript
index 0855c67bb4e..b034f3b06dc 100644
--- a/src/glsl/SConscript
+++ b/src/glsl/SConscript
@@ -17,7 +17,7 @@ env.Prepend(CPPPATH = [
 # Make glcpp-parse.h and glsl_parser.h reachable from the include path.
 env.Append(CPPPATH = [Dir('.').abspath, Dir('glcpp').abspath])
 
-env.Append(YACCFLAGS = '-d')
+env.Append(YACCFLAGS = '-d -p "glcpp_parser_"')
 
 parser_env = env.Clone()
 parser_env.Append(YACCFLAGS = [
diff --git a/src/mesa/SConscript b/src/mesa/SConscript
index 920b545a89b..dba75a26448 100644
--- a/src/mesa/SConscript
+++ b/src/mesa/SConscript
@@ -280,7 +280,7 @@ statetracker_sources = [
     'state_tracker/st_texture.c',
 ]
 
-env.Append(YACCFLAGS = '-d')
+env.Append(YACCFLAGS = '-d -p "_mesa_program_"')
 program_lex = env.CFile('program/lex.yy.c', 'program/program_lexer.l')
 program_parse = env.CFile('program/program_parse.tab.c',
                           'program/program_parse.y')