diff --git a/etc/config/gcc.config b/etc/config/gcc.config
index 89a26ca..4935a8c 100644
--- a/etc/config/gcc.config
+++ b/etc/config/gcc.config
@@ -40,6 +40,7 @@
 else
     ifeq ($(OSNAME),Darwin)
         OS_MAJOR := $(shell uname -r | sed "s/^\([1-9]*\).*/\1/")
+        OS_MINOR := $(shell uname -r | sed "s/^[1-9][0-9]*\.\([1-9]*\).*/\1/")
     endif
 endif
 
@@ -168,14 +169,13 @@
 ifneq ($(CXX_MAJOR),2)
     # gcc 3.x needs to explicitly link with libsupc++ for language support
     # g++ 3.x links with it as well as libstdc++ automatically
-    LDLIBS = -lsupc++
 
-    ifeq ($(OSNAME),Darwin)
-        # link with gcc_eh to resolve the _Unwind_xxx functions
-        # (shouldn't we link with it on all platforms?)
-        LDLIBS += -lgcc_eh
-    endif
-endif   # gcc > 2
+    # Recently, Apple ships a C++ compiler based on LLVM which does not
+    # include a C++ support library; gcc builds on Darwin require a stock
+    # GNU compiler
+
+    LDLIBS = -lsupc++
+endif # gcc > 2
 
 # The flag(s) to use to embed a library search path into generated executables.
 ifeq ($(OSNAME),Linux)
diff --git a/src/x86_64/atomic.s b/src/x86_64/atomic.s
index 616af9b..ce5ce93 100644
--- a/src/x86_64/atomic.s
+++ b/src/x86_64/atomic.s
@@ -26,8 +26,17 @@
  * 
  **************************************************************************/
 
+#if defined (__MACH__)
+// Mac OS X Mach-O assembler: no .type, power of two alignment
+#  define ALIGN_DIR           .align 4
+#  define TYPE_DIR(ignore,ignore2) 
+#else
+#  define ALIGN_DIR           .align 16
+#  define TYPE_DIR(sym,attr)  .type sym, attr
+#endif // __MACH__
+
     .text
-    .align 16
+    ALIGN_DIR
 
 /***************************************************************************
  * extern "C" int8_t __rw_atomic_xchg8 (int8_t *x, int8_t y);
@@ -37,7 +46,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_xchg8
-    .type __rw_atomic_xchg8, @function
+    TYPE_DIR (__rw_atomic_xchg8, STT_FUNC)
 __rw_atomic_xchg8:                 /* ; int8_t (int8_t *x, int8_t y)  */
     movq          %rdi, %rcx       /* ; %rcx = x                      */
     movb          %sil,  %al       /* ; %al = y                       */
@@ -53,7 +62,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_xchg16
-    .type __rw_atomic_xchg16, @function
+    TYPE_DIR (__rw_atomic_xchg16, STT_FUNC)
 __rw_atomic_xchg16:                /* ; int16_t (int16_t *x, int16_t y) */
     movq          %rdi, %rcx       /* ; %rcx = x                        */
     movw          %si,  %ax        /* ; %ax = y                         */
@@ -69,7 +78,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_xchg32
-    .type __rw_atomic_xchg32, @function
+    TYPE_DIR (__rw_atomic_xchg32, STT_FUNC)
 __rw_atomic_xchg32:                /* ; int32_t (int32_t *x, int32_t y) */
     movq          %rdi,  %rcx      /* ; %rcx = x                        */
     movl          %esi,  %eax      /* ; %eax = y                        */
@@ -85,7 +94,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_xchg64
-    .type __rw_atomic_xchg64, @function
+    TYPE_DIR (__rw_atomic_xchg64, STT_FUNC)
 __rw_atomic_xchg64:                /* ; int64_t (int64_t *x, int64_t y) */
     movq          %rdi,  %rcx      /* ; %rcx = x                        */
     movq          %rsi,  %rax      /* ; %rax = y                        */
@@ -101,7 +110,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_add8
-    .type __rw_atomic_add8, @function
+    TYPE_DIR (__rw_atomic_add8, STT_FUNC)
 __rw_atomic_add8:                  /* ; int8_t (int8_t *dst, int8_t inc) */
     movq           %rdi, %rcx      /* ; %rcx = dst                       */
     movl           %esi, %eax      /* ; %eax = inc                       */
@@ -123,7 +132,7 @@
  **************************************************************************/
 
      .globl __rw_atomic_add16
-    .type __rw_atomic_add16, @function
+    TYPE_DIR (__rw_atomic_add16, STT_FUNC)
 __rw_atomic_add16:                 /* ; int16_t (int16_t *dst, int16_t inc) */
     movq           %rdi, %rcx      /* ; %rcx = dst                          */
     movw           %si,  %ax       /* ; %ax = inc                           */
@@ -146,7 +155,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_add32
-    .type __rw_atomic_add32, @function
+    TYPE_DIR (__rw_atomic_add32, STT_FUNC)
 __rw_atomic_add32:                 /* ; int32_t (int32_t *dst, int32_t inc) */
     movq           %rdi, %rcx      /* ; %rcx = dst                          */
     movl           %esi, %edx      /* ; %edx = inc                          */
@@ -169,7 +178,7 @@
  **************************************************************************/
 
     .globl __rw_atomic_add64
-    .type __rw_atomic_add64, @function
+    TYPE_DIR (__rw_atomic_add64, STT_FUNC)
 __rw_atomic_add64:                 /* ; int64_t (int64_t *dst, int64_t inc) */
     movq           %rdi, %rcx      /* ; %rcx = dst                          */
     movq           %rsi, %rdx      /* ; %edx = inc                          */