build: run configure before building dependencies

We need some basic configuration before building dependencies. For
example useful CFLAGS have to be in place to prevent linker errors.

The configure script is run again later with some extra parameters.

GNUmakefile

@@ -169,13 +169,15 @@ dependencies-local:
 	$(MAKE) dependency/build/local
 
 local: clean
+	./configure --environment-only
 	$(MAKE) dependencies-local
 	./configure CFLAGS="-I$(DEPS_INC)" LDFLAGS="-L$(DEPS_LIB)" LD_LIBRARY_PATH="$(DEPS_LIB)"
 	$(MAKE)
 	@echo Run with: LD_LIBRARY_PATH=$(DEPS_LIB) ./vis
 
 standalone: clean
 	[ ! -e dependency/build/local ] || $(MAKE) dependencies-clean
+	./configure --environment-only
 	$(MAKE) dependency/build/libmusl-install
 	PATH=$(DEPS_BIN):$$PATH PKG_CONFIG_PATH= PKG_CONFIG_LIBDIR= $(MAKE) \
 		CC=musl-gcc dependency/build/standalone

configure

@@ -12,6 +12,7 @@ Defaults for the options are specified in brackets.
 
 Configuration:
   --srcdir=DIR            source directory [detected]
+  --environment-only      check environment only, no system libraries
 
 Installation directories:
   --prefix=PREFIX         main installation prefix [/usr/local]
@@ -125,6 +126,7 @@ case "$arg" in
 --bindir=*) BINDIR=${arg#*=} ;;
 --sharedir=*) SHAREDIR=${arg#*=} ;;
 --mandir=*) MANDIR=${arg#*=} ;;
+--environment-only) environmentonly=yes ;;
 --enable-lua|--enable-lua=yes) lua=yes ;;
 --disable-lua|--enable-lua=no) lua=no ;;
 --enable-selinux|--enable-selinux=yes) selinux=yes ;;
@@ -225,6 +227,39 @@ tryldflag LDFLAGS_AUTO -Wl,-z,now
 tryldflag LDFLAGS_AUTO -Wl,-z,relro
 #tryldflag LDFLAGS_AUTO -pie
 
+printf "creating config.mk... "
+
+cmdline=$(quote "$0")
+for i ; do cmdline="$cmdline $(quote "$i")" ; done
+
+exec 3>&1 1>config.mk
+
+cat << EOF
+# This version of config.mk was generated by:
+# $cmdline
+# Any changes made here will be lost if configure is re-run
+SRCDIR = $SRCDIR
+PREFIX = $PREFIX
+EXEC_PREFIX = $EXEC_PREFIX
+BINDIR = $BINDIR
+MANPREFIX = $MANDIR
+SHAREPREFIX = $SHAREDIR
+CC = $CC
+CFLAGS = $CFLAGS
+LDFLAGS = $LDFLAGS
+CFLAGS_STD = $CFLAGS_STD
+LDFLAGS_STD = $LDFLAGS_STD
+CFLAGS_AUTO = $CFLAGS_AUTO
+LDFLAGS_AUTO = $LDFLAGS_AUTO
+EOF
+exec 1>&3 3>&-
+
+printf "done\n"
+
+if test "$environmentonly" = "yes"; then
+	exit 0
+fi
+
 have_pkgconfig=no
 printf "checking for pkg-config... "
 cmdexists pkg-config && have_pkgconfig=yes
@@ -430,30 +465,14 @@ EOF
 	fi
 fi
 
-printf "creating config.mk... "
+printf "completing config.mk... "
 
 cmdline=$(quote "$0")
 for i ; do cmdline="$cmdline $(quote "$i")" ; done
 
-exec 3>&1 1>config.mk
+exec 3>&1 1>>config.mk
 
 cat << EOF
-# This version of config.mk was generated by:
-# $cmdline
-# Any changes made here will be lost if configure is re-run
-SRCDIR = $SRCDIR
-PREFIX = $PREFIX
-EXEC_PREFIX = $EXEC_PREFIX
-BINDIR = $BINDIR
-MANPREFIX = $MANDIR
-SHAREPREFIX = $SHAREDIR
-CC = $CC
-CFLAGS = $CFLAGS
-LDFLAGS = $LDFLAGS
-CFLAGS_STD = $CFLAGS_STD
-LDFLAGS_STD = $LDFLAGS_STD
-CFLAGS_AUTO = $CFLAGS_AUTO
-LDFLAGS_AUTO = $LDFLAGS_AUTO
 CFLAGS_CURSES = $CFLAGS_CURSES
 LDFLAGS_CURSES = $LDFLAGS_CURSES
 CFLAGS_TERMKEY = $CFLAGS_TERMKEY