--- aegisub-3.2.2/configure.ac~	2014-12-08 01:07:09.000000000 +0100
+++ aegisub-3.2.2/configure.ac	2020-03-18 14:58:15.307035878 +0100
@@ -142,7 +142,7 @@
   CFLAGS="$CFLAGS -Wall -Wextra -Wno-unused-parameter -std=gnu99 -pipe -g"
   CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wno-unused-parameter -fno-strict-aliasing -pipe -g"
   AC_CXX_FLAG([-std=c++11])
-  AC_CXX_FLAG([-Wno-c++11-narrowing])
+  AC_CXX_FLAG([-Wno-narrowing])
   AC_C_FLAG([-Wno-unused-local-typedefs])
   AC_CXX_FLAG([-Wno-unused-local-typedefs])
 
@@ -151,8 +151,8 @@
     CFLAGS="$CFLAGS -O0"
     CXXFLAGS="$CXXFLAGS -O0"
   ], [
-    CFLAGS="$CFLAGS -O3"
-    CXXFLAGS="$CXXFLAGS -O3"
+    CFLAGS="$CFLAGS"
+    CXXFLAGS="$CXXFLAGS"
   ])
 ])