Import lib/Makefile-pnacl from pnacl-sfi branch of hg
http://code.google.com/p/nacl-llvm-branches/source/list?repo=compiler-rt&name=pnacl-sfi

Log:
Revision: 1a3a6ffb31ea
pnacl does not support the x86 specific 80bit FP type so we do not need
to bloat libgcc with it.

Also removed support functions for 128bit ints.
Those were guarded by "#if __x86_64" and resulted in
empty object files/bitcode file.

Started adding comments for why other code is NOT included in our libgcc.

CL= http://codereview.chromium.org/7232019/

Rev: 8b41cb76e53e
Move libgcc compiler flags into utman so we can experiment
with a bitcode only version.

BUG= http://code.google.com/p/nativeclient/issues/detail?id=1520

CL= http://codereview.chromium.org/7205042/

Rev: 58885e5e10cf
Enable pow(er) functions with compier-rt/libgcc.
This is needed by the sanboxed components.

Rev: 31d5d91b81cc
Make the pnacl Makefile useful

Rev: 23335816c863
add empty pnacl makefile
diff --git a/lib/Makefile-pnacl b/lib/Makefile-pnacl
new file mode 100644
index 0000000..cd41c58
--- /dev/null
+++ b/lib/Makefile-pnacl
@@ -0,0 +1,82 @@
+# This Makefile builds onacl version of libgcc.a
+#
+# More information on the functions of libgcc can be found at:
+# http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc
+# ../README.txt
+#
+# The following variables are expected to be set externally:
+
+# SRC_DIR
+# CC
+# AR
+# CFLAGS
+
+# pick up .c files from another dir
+vpath %.c ${SRC_DIR}
+
+
+# TODO(robertm): augment/prune this as we gain a better understanding of llc
+# http://code.google.com/p/nativeclient/issues/detail?id=842
+# http://code.google.com/p/nativeclient/issues/detail?id=846
+# http://code.google.com/p/nativeclient/issues/detail?id=821
+#
+# List of unused files in this directory with explanation:
+# (this is still quite incomplete, and there is overlap)
+#
+# complex data type:
+# divdc3.c divsc3.c divxc3.c muldc3.c mulsc3.c mulxc3.c
+# 
+# 128 bit data type:
+# fixdfti.c fixxfti.c fixsfti.c 
+# fixunsdfti.c fixunssfti.c fixunsxfti.c
+# floattidf.c floattisf.c floattixf.c
+# floatuntidf.c floatuntisf.c floatuntixf.c
+# udivti3.c  umodti3.c  modti3.c multi3.c divti3.c
+# powitf2.c
+#
+# 80 bit float type:
+# floatdidf.c  floatdixf.c floatdisf.c
+# powixf2.c
+#
+# long double (ppc?):
+# powitf2.c
+#
+#
+# misc:
+# gcc_personality_v0.c
+# apple_versioning.c
+# trampoline_setup.c
+# enable_execute_stack.c
+# clear_cache.c
+
+SRCS=\
+divdi3.c divsi3.c \
+divmoddi4.c divmodsi4.c \
+fixdfdi.c fixdfsi.c \
+fixsfdi.c fixsfsi.c \
+fixunsdfdi.c fixunsdfsi.c \
+fixunssfdi.c fixunssfsi.c \
+floatdidf.c floatdisf.c \
+floatsidf.c floatsisf.c \
+floatundidf.c floatundisf.c \
+floatunsidf.c floatunsisf.c \
+moddi3.c modsi3.c \
+powisf2.c powidf2.c \
+udivdi3.c udivsi3.c \
+udivmoddi4.c udivmodsi4.c \
+umoddi3.c umodsi3.c 
+
+
+
+
+# NOTE: we build pic so we can use this for both pic and non-pic nexes
+EXTRA_FLAGS= -I${SRC_DIR}
+EXTRA_DEFINES= -D_YUGA_LITTLE_ENDIAN=1 -D_YUGA_BIG_ENDIAN=0
+
+# overwrite default rule to make sure nothig unexpected happens
+%.o : %.c
+	$(CC) -c $(CFLAGS) ${EXTRA_DEFINES} ${EXTRA_FLAGS} $< -o $@
+
+# The main target of this Makefile
+libgcc.a: $(SRCS:.c=.o)
+	$(AR) rc $@ $^