Allow toolchain to determine ar

Makefile.in

@@ -55,6 +55,8 @@ PIC_CFLAGS = @PIC_CFLAGS@
 CTARGET = @CTARGET@
 LDTARGET = @LDTARGET@
 MKLIB = @MKLIB@
+AR = @AR@
+ARFLAGS = crus
 CC_MM = @CC_MM@
 
 ifeq (macho, $(ABI))
@@ -185,7 +187,7 @@ $(objroot)lib/$(LIBJEMALLOC)_s.$(A) : $(COBJS)
 
 $(STATIC_LIBS):
 	@mkdir -p $(@D)
-	$(MKLIB) $+
+	$(AR) $(ARFLAGS) $@ $+
 
 $(objroot)test/bitmap$(EXE): $(objroot)src/bitmap.$(O)
 

configure.ac

@@ -226,9 +226,13 @@ PIC_CFLAGS='-fPIC -DPIC'
 CTARGET='-o $@'
 LDTARGET='-o $@'
 EXTRA_LDFLAGS=
-MKLIB='ar crus $@'
 CC_MM=1
 
+AN_MAKEVAR([AR], [AC_PROG_AR])
+AN_PROGRAM([ar], [AC_PROG_AR])
+AC_DEFUN([AC_PROG_AR], [AC_CHECK_TOOL(AR, ar, :)])
+AC_PROG_AR
+
 dnl Platform-specific settings.  abi and RPATH can probably be determined
 dnl programmatically, but doing so is error-prone, which makes it generally
 dnl not worth the trouble.
@@ -310,7 +314,8 @@ case "${host}" in
 	  EXTRA_LDFLAGS="-link -DEBUG"
 	  CTARGET='-Fo$@'
 	  LDTARGET='-Fe$@'
-	  MKLIB='lib -nologo -out:$@'
+	  AR='lib'
+	  ARFLAGS='-nologo -out:'
 	  CC_MM=
         else
 	  importlib="${so}"
@@ -403,7 +408,6 @@ AC_SUBST([enable_autogen])
 
 AC_PROG_INSTALL
 AC_PROG_RANLIB
-AC_PATH_PROG([AR], [ar], [false], [$PATH])
 AC_PATH_PROG([LD], [ld], [false], [$PATH])
 AC_PATH_PROG([AUTOCONF], [autoconf], [false], [$PATH])