OSX Portability issues

[Siesh1oo]

  Hi, this patch resolves some build issues on OSX 10.9 (earlier versions are probably affected, too).

   - Apple's gcc and clang cannot build '-static' binaries (crt0.o missing).
   - The '-soname' option is '-dylib_install_name' on OSX.
   - For linking, the order of options matters.
   - minisat::memUsedPeak() definition was not matching the declaration.
   - unused arguments need to be (void) casted to avoid a compiler warning.

 Sincerely,
 H.

diff --git a/Makefile b/Makefile
index ceb9d77..7782c85 100644
--- a/Makefile
+++ b/Makefile
@@ -62,6 +62,14 @@ SORELEASE?=.0#   Declare empty to leave out from library file name.
 MINISAT_CXXFLAGS = -I. -D __STDC_LIMIT_MACROS -D __STDC_FORMAT_MACROS -Wall -Wno-parentheses -Wextra
 MINISAT_LDFLAGS  = -Wall -lz

+ifeq (Darwin,$(findstring Darwin,$(shell uname)))
+   SHARED_LDFLAGS += -shared -Wl,-dylib_install_name,$(MINISAT_DLIB).$(SOMAJOR)
+   RELEASE_LDFLAGS +=
+else
+   SHARED_LDFLAGS += -shared -Wl,-soname,$(MINISAT_DLIB).$(SOMAJOR)
+   RELEASE_LDFLAGS += -static
+endif
+
 ECHO=@echo
 ifeq ($(VERB),)
 VERB=@
@@ -96,9 +104,9 @@ $(BUILD_DIR)/dynamic/%.o:            MINISAT_CXXFLAGS +=$(MINISAT_REL) $(MINISAT_FPIC)

 ## Build-type Link-flags:
 $(BUILD_DIR)/profile/bin/$(MINISAT):       MINISAT_LDFLAGS += -pg
-$(BUILD_DIR)/release/bin/$(MINISAT):       MINISAT_LDFLAGS += --static $(MINISAT_RELSYM)
+$(BUILD_DIR)/release/bin/$(MINISAT):       MINISAT_LDFLAGS += $(RELEASE_LDFLAGS) $(MINISAT_RELSYM)
 $(BUILD_DIR)/profile/bin/$(MINISAT_CORE):  MINISAT_LDFLAGS += -pg
-$(BUILD_DIR)/release/bin/$(MINISAT_CORE):  MINISAT_LDFLAGS += --static $(MINISAT_RELSYM)
+$(BUILD_DIR)/release/bin/$(MINISAT_CORE):  MINISAT_LDFLAGS += $(RELEASE_LDFLAGS) $(MINISAT_RELSYM)

 ## Executable dependencies
 $(BUILD_DIR)/release/bin/$(MINISAT):       $(BUILD_DIR)/release/minisat/simp/Main.o $(BUILD_DIR)/release/lib/$(MINISAT_SLIB)
@@ -162,7 +170,7 @@ $(BUILD_DIR)/dynamic/lib/$(MINISAT_DLIB).$(SOMAJOR).$(SOMINOR)$(SORELEASE)\
  $(BUILD_DIR)/dynamic/lib/$(MINISAT_DLIB):
    $(ECHO) Linking Shared Library: $@
    $(VERB) mkdir -p $(dir $@)
-   $(VERB) $(CXX) $(MINISAT_LDFLAGS) $(LDFLAGS) -o $@ -shared -Wl,-soname,$(MINISAT_DLIB).$(SOMAJOR) $^
+   $(VERB) $(CXX) $^ $(SHARED_LDFLAGS) $(MINISAT_LDFLAGS) $(LDFLAGS) -o $@
    $(VERB) ln -sf $(MINISAT_DLIB).$(SOMAJOR).$(SOMINOR)$(SORELEASE) $(BUILD_DIR)/dynamic/lib/$(MINISAT_DLIB).$(SOMAJOR)
    $(VERB) ln -sf $(MINISAT_DLIB).$(SOMAJOR) $(BUILD_DIR)/dynamic/lib/$(MINISAT_DLIB)

diff --git a/minisat/utils/System.cc b/minisat/utils/System.cc
index 21aa4ff..b353bec 100644
--- a/minisat/utils/System.cc
+++ b/minisat/utils/System.cc
@@ -77,7 +77,7 @@ double Minisat::memUsed() {
     struct rusage ru;
     getrusage(RUSAGE_SELF, &ru);
     return (double)ru.ru_maxrss / 1024; }
-double Minisat::memUsedPeak() { return memUsed(); }
+double Minisat::memUsedPeak(bool strictlyPeak) { (void) strictlyPeak; return memUsed(); }


 #elif defined(__APPLE__)
@@ -87,11 +87,11 @@ double Minisat::memUsed() {
     malloc_statistics_t t;
     malloc_zone_statistics(NULL, &t);
     return (double)t.max_size_in_use / (1024*1024); }
-double Minisat::memUsedPeak() { return memUsed(); }
+double Minisat::memUsedPeak(bool strictlyPeak) { (void) strictlyPeak; return memUsed(); }

 #else
 double Minisat::memUsed()     { return 0; }
-double Minisat::memUsedPeak() { return 0; }
+double Minisat::memUsedPeak(bool strictlyPeak) { (void) strictlyPeak; return 0; }
 #endif