diff --git a/README.md b/README.md
index 3d15517..5e8aa35 100644
--- a/README.md
+++ b/README.md
@@ -22,15 +22,15 @@ The pixel format and screen coordinates are standardized, however, the HID input
 
 ## Platform: null
 This platform has a very simple implementation, that is essentially a no-op for any possible target. It's meant for running a basic test before one makes a proper port.
-1. `cc src/main.c -O2 -D unigi_flag_platform_null -o unigi.exe`
+1. `cc src/main.c -Dunigi_flag_platform_null -o unigi.exe`
 
 ## Platform: sdl1
 This platform implements the highly compatible SDL 1.2, which runs on all sorts of versions of Linux and Windows, as well as big endian CPUs.
-1. `cc src/main.c -O2 -D unigi_flag_platform_sdl1 -l SDL -o unigi.exe`
+1. `cc src/main.c -Dunigi_flag_platform_sdl1 -l SDL -o unigi.exe`
 
 ## Advanced configuration
 ### No stdint.h
-If no stdint.h is available, one must define `-D unigi_flag_nostdint` and also one of `-D unigi_flag_alu_*bit` (`*` = 8, 16, 32, 64), depending on how wide the ALU of the target CPU is.
+If no stdint.h is available, one must define `unigi_flag_nostdint` and also one of `unigi_flag_alu_*bit` (`*` = 8, 16, 32, 64), depending on how wide the ALU of the target CPU is.
 
 ### Fixed point numbers
-If fixed point is wished instead of float, one can define `-D unigi_flag_fixedpoint`. This uses the external fptc-lib headers.
+If fixed point is wished instead of float, one can define `unigi_flag_fixedpoint`. This uses the external fptc-lib headers.