Add EXTRA_CFLAGS with -Werror for CI

.github/workflows/main.yml

@@ -25,6 +25,7 @@ jobs:
 
     env:
       CC: ${{ matrix.CC }}
+      EXTRA_CFLAGS: "-Werror"
     steps:
     - uses: actions/checkout@v2
       with:

README.md

@@ -111,6 +111,7 @@ sudo make install
 - `WAYLAND=(0|1)`: Disable/Enable wayland support. (Default: 1 (enabled))
 - `SERVICEDIR_SYSTEMD=<PATH>`: The path to put the systemd user service file. Unused, if `SYSTEMD=0`. (Default: detected via `pkg-config`)
 - `SERVICEDIR_DBUS=<PATH>`: The path to put the dbus service file. (Default: detected via `pkg-config`)
+- `EXTRA_CFLAGS=<FLAGS>`: Additional flags for the compiler.
 
 **Make sure to run all make calls with the same parameter set. So when building with `make PREFIX=/usr`, you have to install it with `make PREFIX=/usr install`, too.**
 

config.mk

@@ -6,6 +6,7 @@ DATADIR ?= ${PREFIX}/share
 # around for backwards compatibility
 MANPREFIX ?= ${DATADIR}/man
 MANDIR ?= ${MANPREFIX}
+EXTRA_CFLAGS ?=
 
 DOXYGEN ?= doxygen
 FIND ?= find
@@ -36,7 +37,7 @@ endif
 
 # flags
 DEFAULT_CPPFLAGS = -D_DEFAULT_SOURCE -DVERSION=\"${VERSION}\"
-DEFAULT_CFLAGS   = -g --std=gnu99 -pedantic -Wall -Wno-overlength-strings -Os ${STATIC} ${ENABLE_WAYLAND}
+DEFAULT_CFLAGS   = -g --std=gnu99 -pedantic -Wall -Wno-overlength-strings -Os ${STATIC} ${ENABLE_WAYLAND} ${EXTRA_CFLAGS}
 DEFAULT_LDFLAGS  = -lm -lrt
 
 CPPFLAGS_DEBUG := -DDEBUG_BUILD