In file included from src/asm/charmap.c:22:
include/hashmap.h:18:15: error: expected parameter declarator
static_assert(HALF_HASH_NB_BITS * 2 == HASH_NB_BITS, "");
              ^
include/hashmap.h:17:27: note: expanded from macro 'HALF_HASH_NB_BITS'
#define HALF_HASH_NB_BITS 16
                          ^
include/hashmap.h:18:15: error: expected ')'
include/hashmap.h:17:27: note: expanded from macro 'HALF_HASH_NB_BITS'
#define HALF_HASH_NB_BITS 16
                          ^
include/hashmap.h:18:14: note: to match this '('
static_assert(HALF_HASH_NB_BITS * 2 == HASH_NB_BITS, "");
             ^
include/hashmap.h:18:1: warning: type specifier missing, defaults to 'int' [-Wimplicit-int]
static_assert(HALF_HASH_NB_BITS * 2 == HASH_NB_BITS, "");
^
1 warning and 2 errors generated.

--- Makefile.orig	2021-03-10 06:20:18 UTC
+++ Makefile
@@ -35,7 +35,7 @@ WARNFLAGS	:= -Wall
 # Overridable CFLAGS
 CFLAGS		?= -O3 -flto -DNDEBUG
 # Non-overridable CFLAGS
-REALCFLAGS	:= ${CFLAGS} ${WARNFLAGS} -std=gnu11 -D_POSIX_C_SOURCE=200809L \
+REALCFLAGS	:= ${CFLAGS} ${WARNFLAGS} -std=gnu11 \
 		   -Iinclude
 # Overridable LDFLAGS
 LDFLAGS		?=