-pedantic -> -Wpedantic

Bug: https://codeberg.org/dwl/dwl/issues/584

Makefile

@@ -6,7 +6,7 @@ include config.mk
 # flags for compiling
 DWLCPPFLAGS = -I. -DWLR_USE_UNSTABLE -D_POSIX_C_SOURCE=200809L \
 	-DVERSION=\"$(VERSION)\" $(XWAYLAND)
-DWLDEVCFLAGS = -g -pedantic -Wall -Wextra -Wdeclaration-after-statement \
+DWLDEVCFLAGS = -g -Wpedantic -Wall -Wextra -Wdeclaration-after-statement \
 	-Wno-unused-parameter -Wshadow -Wunused-macros -Werror=strict-prototypes \
 	-Werror=implicit -Werror=return-type -Werror=incompatible-pointer-types \
 	-Wfloat-conversion

config.mk

@@ -14,4 +14,7 @@ XLIBS =
 #XWAYLAND = -DXWAYLAND
 #XLIBS = xcb xcb-icccm
 
-CC = gcc
+# dwl itself only uses C99 features, but wlroots' headers use anonymous unions (C11).
+# To avoid warnings about them, we do not use -std=c99 and instead of using the
+# gmake default 'CC=c99', we use cc.
+CC = cc