diff -rupN nsis-3.04-src/SCons/Config/gnu nsis-3.04-src-new/SCons/Config/gnu
--- nsis-3.04-src/SCons/Config/gnu	2017-10-06 21:30:20.000000000 +0200
+++ nsis-3.04-src-new/SCons/Config/gnu	2019-07-29 18:00:46.633960946 +0200
@@ -1,5 +1,7 @@
 print("Using GNU tools configuration")
 
+import os
+
 Import('defenv')
 
 ### imports
@@ -114,6 +116,7 @@ makensis_env.Append(CPPPATH = ['#$BUILD_
 
 if not defenv['DEBUG']:
 	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
@@ -190,6 +193,7 @@ conf.Finish()
 
 ### cross-platform util environment adjustments
 
+cp_util_env.Append(CCFLAGS = os.getenv('RPM_OPT_FLAGS'))
 conf = FlagsConfigure(cp_util_env)
 if not defenv['DEBUG'] and defenv['STRIP'] and defenv['STRIP_CP']:
 	TestStrip(conf)                                 # strip