allow the use of non-system wlroots library

References: https://codeberg.org/dwl/dwl/issues/646#issuecomment-2032644

Makefile

@@ -12,9 +12,9 @@ DWLDEVCFLAGS = -g -Wpedantic -Wall -Wextra -Wdeclaration-after-statement \
 	-Wfloat-conversion
 
 # CFLAGS / LDFLAGS
-PKGS      = wlroots-0.19 wayland-server xkbcommon libinput $(XLIBS)
-DWLCFLAGS = `$(PKG_CONFIG) --cflags $(PKGS)` $(DWLCPPFLAGS) $(DWLDEVCFLAGS) $(CFLAGS)
-LDLIBS    = `$(PKG_CONFIG) --libs $(PKGS)` -lm $(LIBS)
+PKGS      = wayland-server xkbcommon libinput $(XLIBS)
+DWLCFLAGS = `$(PKG_CONFIG) --cflags $(PKGS)` $(WLR_INCS) $(DWLCPPFLAGS) $(DWLDEVCFLAGS) $(CFLAGS)
+LDLIBS    = `$(PKG_CONFIG) --libs $(PKGS)` $(WLR_LIBS) -lm $(LIBS)
 
 all: dwl
 dwl: dwl.o util.o

config.mk

@@ -8,6 +8,22 @@ PREFIX = /usr/local
 MANDIR = $(PREFIX)/share/man
 DATADIR = $(PREFIX)/share
 
+# Allow using an alternative wlroots installations
+# This has to have all the includes required by wlroots, e.g:
+# Assuming wlroots git repo is "${PWD}/wlroots" and you only ran "meson setup build && ninja -C build"
+#WLR_INCS = -I/usr/include/pixman-1 -I/usr/include/elogind -I/usr/include/libdrm \
+#	-I$(PWD)/wlroots/include
+# Set -rpath to avoid using the wrong library.
+#WLR_LIBS = -Wl,-rpath,$(PWD)/wlroots/build -L$(PWD)/wlroots/build -lwlroots-0.19
+
+# Assuming you ran "meson setup --prefix ${PWD}/0.19 build && ninja -C build install"
+#WLR_INCS = -I/usr/include/pixman-1 -I/usr/include/elogind -I/usr/include/libdrm \
+#	-I$(PWD)/wlroots/0.19/include/wlroots-0.19
+#WLR_LIBS = -Wl,-rpath,$(PWD)/wlroots/0.19/lib64 -L$(PWD)/wlroots/0.19/lib64 -lwlroots-0.19
+
+WLR_INCS = `$(PKG_CONFIG) --cflags wlroots-0.19`
+WLR_LIBS = `$(PKG_CONFIG) --libs wlroots-0.19`
+
 XWAYLAND =
 XLIBS =
 # Uncomment to build XWayland support