On Windows, detect if DLLs have too many symbols; trac #5987

The test isn't very pretty; it involves trawling through the
objdump -p output. I couldn't find an easier way, unfortuantely.

configure.ac

@@ -336,6 +336,7 @@ then
     CC="${mingwbin}gcc.exe"
     LD="${mingwbin}ld.exe"
     NM="${mingwbin}nm.exe"
+    OBJDUMP="${mingwbin}objdump.exe"
     fp_prog_ar="${mingwbin}ar.exe"
 
     if ! test -d inplace/perl ||
@@ -446,6 +447,12 @@ FP_ARG_WITH_PATH_GNU_PROG([NM], [nm], [nm])
 NmCmd="$NM"
 AC_SUBST([NmCmd])
 
+dnl ** Which objdump to use?
+dnl --------------------------------------------------------------
+FP_ARG_WITH_PATH_GNU_PROG([OBJDUMP], [objdump], [objdump])
+ObjdumpCmd="$OBJDUMP"
+AC_SUBST([ObjdumpCmd])
+
 dnl ** Which LLVM llc to use?
 dnl --------------------------------------------------------------
 FP_ARG_WITH_PATH_GNU_PROG_OPTIONAL([LLC], [llc])

mk/config.mk.in

@@ -714,6 +714,7 @@ DTRACE			= @DtraceCmd@
 
 LD = @LdCmd@
 NM = @NmCmd@
+OBJDUMP = @ObjdumpCmd@
 
 LLC = @LlcCmd@
 OPT = @OptCmd@

rules/build-package-way.mk

@@ -69,6 +69,9 @@ $$($1_$2_$3_LIB) : $$($1_$2_$3_ALL_OBJS) $$(ALL_RTS_LIBS) $$($1_$2_$3_DEPS_LIBS)
 	 $$(addprefix -l,$$($1_$2_EXTRA_LIBRARIES)) \
          -no-auto-link-packages \
          -o $$@
+# Now check that the DLL doesn't have too many symbols. See trac #5987.
+	case `$$(OBJDUMP) -p $$@ | sed -n "1,/^.Ordinal\/Name Pointer/ D; p; /^$$$$/ q" | grep "\[ *0\]" | wc -l` in 1) echo DLL $$@ OK;; 0) echo No symbols in DLL $$@; exit 1;; [0-9]*) echo Too many symbols in DLL $$@; exit 1;; *) echo bad DLL $$@; exit 1;; esac
+
 else
 $$($1_$2_$3_LIB) : $$($1_$2_$3_ALL_OBJS) $$(ALL_RTS_LIBS) $$($1_$2_$3_DEPS_LIBS)
 	$$(call cmd,$1_$2_HC) $$($1_$2_$3_ALL_HC_OPTS) $$($1_$2_$3_ALL_OBJS) \