diff -ur nsis-2.43-src-debian-debug-opt/SCons/Config/gnu nsis-2.43-src-rpm-opt/SCons/Config/gnu
--- nsis-2.43-src-debian-debug-opt/SCons/Config/gnu	2009-02-25 08:35:01.000000000 +0100
+++ nsis-2.43-src-rpm-opt/SCons/Config/gnu	2009-02-25 13:45:40.000000000 +0100
@@ -1,5 +1,7 @@
 print "Using GNU tools configuration"
 
+import os
+
 Import('defenv')
 
 ### imports
@@ -95,7 +97,7 @@
 	makensis_env.Append(LINKFLAGS = '-g')             # debugging
 	makensis_env.Append(CCFLAGS = '-g')               # debugging
 if not defenv['DEBUG'] and defenv['OPT']:
-	makensis_env.Append(CCFLAGS = ['-O2'])            # optimize
+	makensis_env.Append(CCFLAGS = os.getenv('RPM_OPT_FLAGS'))            # optimize
 makensis_env.Append(CFLAGS = ['-Wall'])                   # all warnings
 makensis_env.Append(CXXFLAGS = ['-Wno-non-virtual-dtor']) # ignore virtual dtor warnings
 makensis_env.Append(CXXFLAGS = ['-Wall'])                 # all warnings
@@ -135,7 +137,7 @@
 	cp_util_env.Append(LINKFLAGS = '-g')        # debugging
 	cp_util_env.Append(CCFLAGS = '-g')          # debugging
 if not defenv['DEBUG'] and defenv['OPT']:
-	cp_util_env.Append(CCFLAGS = ['-O2'])             # optimize
+	cp_util_env.Append(CCFLAGS = os.getenv('RPM_OPT_FLAGS'))             # optimize
 cp_util_env.Append(CCFLAGS = ['-Wall'])             # all warnings
 cp_util_env.Append(CCFLAGS = ['-fno-strict-aliasing']) # not safe for strict aliasing