diff --git a/mythes/makefile.mk b/mythes/makefile.mk
index f373a5d16262..b1667c331d93 100644
--- a/mythes/makefile.mk
+++ b/mythes/makefile.mk
@@ -61,6 +61,8 @@ CONFIGURE_FLAGS= --disable-shared --with-pic
 
 .IF "$(COM)"=="C52" && "$(CPU)"=="U"
 LCL_CONFIGURE_CFLAGS+=-m64
+.ELIF "$(OS)"=="AIX"
+LCL_CONFIGURE_CFLAG+=-D_LINUX_SOURCE_COMPAT
 .ENDIF
 
 .IF "$(SYSBASE)"!=""