Index: kernel/Makefile
===================================================================
--- kernel/Makefile	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
+++ kernel/Makefile	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -87,5 +87,5 @@
 INCLUDES_FLAGS = $(addprefix -I,$(INCLUDES))
 
-DEFS = -DKERNEL -DRELEASE=$(RELEASE) "-DCOPYRIGHT=$(COPYRIGHT)" "-DNAME=$(NAME)" -D__$(BITS)_BITS__ -D__$(ENDIANESS)__ -D__OPAQUE_ERRNO__
+DEFS = -DKERNEL -DRELEASE=$(RELEASE) "-DCOPYRIGHT=$(COPYRIGHT)" "-DNAME=$(NAME)" -D__$(BITS)_BITS__ -D__$(ENDIANESS)__
 
 COMMON_CFLAGS = $(INCLUDES_FLAGS) -O$(OPTIMIZATION) -imacros $(CONFIG_HEADER) \
Index: uspace/Makefile.common
===================================================================
--- uspace/Makefile.common	(revision e211ea04fccf33d4cb2092f630a29e893e096a02)
+++ uspace/Makefile.common	(revision 847844a5c1c6014e479cb00bf10c9d740927aa2d)
@@ -177,6 +177,5 @@
 	-ffreestanding -fno-builtin -nostdlib -nostdinc -fexec-charset=UTF-8 \
 	-finput-charset=UTF-8 -D__$(ENDIANESS)__ -fno-common \
-	-fdebug-prefix-map=$(realpath $(ROOT_PATH))=. \
-	-D__OPAQUE_ERRNO__
+	-fdebug-prefix-map=$(realpath $(ROOT_PATH))=.
 
 GCC_CFLAGS = -ffunction-sections -Wall -Wextra -Wno-clobbered \