diff -ur nsis-2.34-src/SCons/Config/gnu nsis-2.34-src-RPM_OPT_FLAGS/SCons/Config/gnu
--- nsis-2.34-src/SCons/Config/gnu	2007-11-14 07:20:44.000000000 +0100
+++ nsis-2.34-src-RPM_OPT_FLAGS/SCons/Config/gnu	2008-01-13 22:17:41.000000000 +0100
@@ -1,5 +1,7 @@
 print "Using GNU tools configuration"
 
+import os
+
 Import('defenv')
 
 ### imports
@@ -80,7 +82,7 @@
 makensis_env = defenv.Clone()
 
 if not defenv['DEBUG']:
-	makensis_env.Append(CCFLAGS = '-O2')            # optimize
+	makensis_env.Append(CCFLAGS = os.getenv('RPM_OPT_FLAGS'))            # optimize
 makensis_env.Append(CCFLAGS = '-Wall')            # all warnings
 makensis_env.Append(CXXFLAGS = '-Wno-non-virtual-dtor') # ignore virtual dtor warnings
 
@@ -113,7 +115,7 @@
 cp_util_env = defenv.Clone()
 
 if not defenv['DEBUG']:
-	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