Improve library checks
diff --git a/src/check-defs.sh b/src/check-defs.sh
new file mode 100755
index 0000000..d7a8ec2
--- /dev/null
+++ b/src/check-defs.sh
@@ -0,0 +1,44 @@
+#!/bin/sh
+
+LC_ALL=C
+export LC_ALL
+
+test -z "$srcdir" && srcdir=.
+test -z "$MAKE" && MAKE=make
+stat=0
+
+if which nm 2>/dev/null >/dev/null; then
+ :
+else
+ echo "check-defs.sh: 'nm' not found; skipping test"
+ exit 77
+fi
+
+defs="harfbuzz.def"
+$MAKE $defs > /dev/null
+tested=false
+for def in $defs; do
+ lib=`echo "$def" | sed 's/[.]def$//;s@.*/@@'`
+ so=.libs/lib${lib}.so
+
+ EXPORTED_SYMBOLS="`nm "$so" | grep ' [BCDGINRSTVW] ' | grep -v ' _fini\>\| _init\>\| _fdata\>\| _ftext\>\| __bss_start\>\| __bss_start__\>\| __bss_end__\>\| _edata\>\| _end\>\| _bss_end__\>\| __end__\>' | cut -d' ' -f3`"
+
+ if test -f "$so"; then
+
+ echo "Checking that $so has the same symbol list as $def"
+ {
+ echo EXPORTS
+ echo "$EXPORTED_SYMBOLS"
+ # cheat: copy the last line from the def file!
+ tail -n1 "$def"
+ } | diff "$def" - >&2 || stat=1
+
+ tested=true
+ fi
+done
+if ! $tested; then
+ echo "check-defs.sh: libharfbuzz shared library not found; skipping test"
+ exit 77
+fi
+
+exit $stat
