build: Replace `make config` with a `./configure` script

This lets us do more traditional out-of-tree builds like

    $ ../path/to/bfs/configure
    $ make

The .mk files are moved from ./config to ./build, mostly so that
./configure will auto-complete easily.

1 files changed, 100 insertions, 0 deletions

diff --git a/build/pkgconf.sh b/build/pkgconf.sh
new file mode 100755
index 0000000..96e4bf1
--- /dev/null
+++ b/build/pkgconf.sh
@@ -0,0 +1,100 @@
+#!/bin/sh
+
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
+
+# pkg-config wrapper with hardcoded fallbacks
+
+set -eu
+
+MODE=
+case "${1:-}" in
+    --*)
+        MODE="$1"
+        shift
+esac
+
+if [ $# -lt 1 ]; then
+    exit
+fi
+
+case "$XNOLIBS" in
+    y|1)
+        exit 1
+esac
+
+if [ -z "$MODE" ]; then
+    # Check whether the libraries exist at all
+    for LIB; do
+        # Check ${USE_$LIB}
+        USE_LIB="USE_$(printf '%s' "$LIB" | tr 'a-z-' 'A-Z_')"
+        eval "USE=\"\${$USE_LIB:-}\""
+        case "$USE" in
+            y|1)
+                continue
+                ;;
+            n|0)
+                exit 1
+                ;;
+        esac
+
+        CFLAGS=$("$0" --cflags "$LIB") || exit 1
+        LDFLAGS=$("$0" --ldflags "$LIB") || exit 1
+        LDLIBS=$("$0" --ldlibs "$LIB") || exit 1
+        build/cc.sh $CFLAGS $LDFLAGS build/use/$LIB.c $LDLIBS || exit 1
+    done
+fi
+
+# Defer to pkg-config if possible
+if command -v "${XPKG_CONFIG:-}" >/dev/null 2>&1; then
+    case "$MODE" in
+        --cflags)
+            "$XPKG_CONFIG" --cflags "$@"
+            ;;
+        --ldflags)
+            "$XPKG_CONFIG" --libs-only-L --libs-only-other "$@"
+            ;;
+        --ldlibs)
+            "$XPKG_CONFIG" --libs-only-l "$@"
+            ;;
+    esac
+
+    exit
+fi
+
+# pkg-config unavailable, emulate it ourselves
+CFLAGS=""
+LDFLAGS=""
+LDLIBS=""
+
+for LIB; do
+    case "$LIB" in
+        libacl)
+            LDLIB=-lacl
+            ;;
+        libcap)
+            LDLIB=-lcap
+            ;;
+        libselinux)
+            LDLIB=-lselinux
+            ;;
+        liburing)
+            LDLIB=-luring
+            ;;
+        oniguruma)
+            LDLIB=-lonig
+            ;;
+        *)
+            printf 'error: Unknown package %s\n' "$LIB" >&2
+            exit 1
+            ;;
+    esac
+
+    LDLIBS="$LDLIBS$LDLIB "
+done
+
+case "$MODE" in
+    --ldlibs)
+        printf '%s\n' "$LDLIBS"
+    ;;
+esac