Merge #10544: Update to LevelDB 1.20

3ee3d04 Add extra LevelDB source to Makefile (MarcoFalke)
2424989 leveldb: enable runtime-detected crc32 instructions (Cory Fields)
cf44e4c Squashed 'src/leveldb/' changes from a31c8aa..196962f (Pieter Wuille)

Tree-SHA512: 19ade77e3f6265507b3ab7b9aa5150d378aa0751e24ac7a61567b0f720a566cedc6c3d3336da17a3bd2b5d068ee86600d96a15228f78bd20ccf98c8fc9041a91

Author: laanwj

configure.ac

@@ -236,6 +236,12 @@ if test "x$CXXFLAGS_overridden" = "xno"; then
   AX_CHECK_COMPILE_FLAG([-Wunused-local-typedef],[CXXFLAGS="$CXXFLAGS -Wno-unused-local-typedef"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wdeprecated-register],[CXXFLAGS="$CXXFLAGS -Wno-deprecated-register"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wimplicit-fallthrough],[CXXFLAGS="$CXXFLAGS -Wno-implicit-fallthrough"],,[[$CXXFLAG_WERROR]])
+
+  # Check for optional instruction set support. Enabling these does _not_ imply that all code will
+  # be compiled with them, rather that specific objects/libs may use them after checking for runtime
+  # compatibility.
+  AX_CHECK_COMPILE_FLAG([-msse4.2],[[enable_sse42=yes; SSE42_CXXFLAGS="-msse4.2"]],,[[$CXXFLAG_WERROR]])
+
 fi
 CPPFLAGS="$CPPFLAGS -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS"
 
@@ -1114,6 +1120,7 @@ AM_CONDITIONAL([USE_QRCODE], [test x$use_qr = xyes])
 AM_CONDITIONAL([USE_LCOV],[test x$use_lcov = xyes])
 AM_CONDITIONAL([GLIBC_BACK_COMPAT],[test x$use_glibc_compat = xyes])
 AM_CONDITIONAL([HARDEN],[test x$use_hardening = xyes])
+AM_CONDITIONAL([ENABLE_SSE42],[test x$enable_sse42 = xyes])
 
 AC_DEFINE(CLIENT_VERSION_MAJOR, _CLIENT_VERSION_MAJOR, [Major version])
 AC_DEFINE(CLIENT_VERSION_MINOR, _CLIENT_VERSION_MINOR, [Minor version])
@@ -1146,6 +1153,7 @@ AC_SUBST(HARDENED_CPPFLAGS)
 AC_SUBST(HARDENED_LDFLAGS)
 AC_SUBST(PIC_FLAGS)
 AC_SUBST(PIE_FLAGS)
+AC_SUBST(SSE42_CXXFLAGS)
 AC_SUBST(LIBTOOL_APP_LDFLAGS)
 AC_SUBST(USE_UPNP)
 AC_SUBST(USE_QRCODE)

src/Makefile.am

@@ -380,6 +380,7 @@ bitcoind_LDADD = \
   $(LIBBITCOIN_CONSENSUS) \
   $(LIBBITCOIN_CRYPTO) \
   $(LIBLEVELDB) \
+  $(LIBLEVELDB_SSE42) \
   $(LIBMEMENV) \
   $(LIBSECP256K1)
 

src/Makefile.bench.include

@@ -39,6 +39,7 @@ bench_bench_bitcoin_LDADD = \
   $(LIBBITCOIN_CONSENSUS) \
   $(LIBBITCOIN_CRYPTO) \
   $(LIBLEVELDB) \
+  $(LIBLEVELDB_SSE42) \
   $(LIBMEMENV) \
   $(LIBSECP256K1) \
   $(LIBUNIVALUE)

src/Makefile.leveldb.include

@@ -4,12 +4,15 @@
 
 LIBLEVELDB_INT = leveldb/libleveldb.a
 LIBMEMENV_INT  = leveldb/libmemenv.a
+LIBLEVELDB_SSE42_INT  = leveldb/libleveldb_sse42.a
 
 EXTRA_LIBRARIES += $(LIBLEVELDB_INT)
 EXTRA_LIBRARIES += $(LIBMEMENV_INT)
+EXTRA_LIBRARIES += $(LIBLEVELDB_SSE42_INT)
 
 LIBLEVELDB += $(LIBLEVELDB_INT)
 LIBMEMENV += $(LIBMEMENV_INT)
+LIBLEVELDB_SSE42 = $(LIBLEVELDB_SSE42_INT)
 
 LEVELDB_CPPFLAGS += -I$(srcdir)/leveldb/include
 LEVELDB_CPPFLAGS += -I$(srcdir)/leveldb/helpers/memenv
@@ -74,6 +77,7 @@ leveldb_libleveldb_a_SOURCES += leveldb/table/merger.h
 leveldb_libleveldb_a_SOURCES += leveldb/table/format.h
 leveldb_libleveldb_a_SOURCES += leveldb/table/iterator_wrapper.h
 leveldb_libleveldb_a_SOURCES += leveldb/util/crc32c.h
+leveldb_libleveldb_a_SOURCES += leveldb/util/env_posix_test_helper.h
 leveldb_libleveldb_a_SOURCES += leveldb/util/arena.h
 leveldb_libleveldb_a_SOURCES += leveldb/util/random.h
 leveldb_libleveldb_a_SOURCES += leveldb/util/posix_logger.h
@@ -135,3 +139,11 @@ leveldb_libmemenv_a_CPPFLAGS = $(leveldb_libleveldb_a_CPPFLAGS)
 leveldb_libmemenv_a_CXXFLAGS = $(leveldb_libleveldb_a_CXXFLAGS)
 leveldb_libmemenv_a_SOURCES =  leveldb/helpers/memenv/memenv.cc
 leveldb_libmemenv_a_SOURCES += leveldb/helpers/memenv/memenv.h
+
+leveldb_libleveldb_sse42_a_CPPFLAGS = $(leveldb_libleveldb_a_CPPFLAGS)
+leveldb_libleveldb_sse42_a_CXXFLAGS = $(leveldb_libleveldb_a_CXXFLAGS)
+if ENABLE_SSE42
+leveldb_libleveldb_sse42_a_CPPFLAGS += -DLEVELDB_PLATFORM_POSIX_SSE
+leveldb_libleveldb_sse42_a_CXXFLAGS += $(SSE42_CXXFLAGS)
+endif
+leveldb_libleveldb_sse42_a_SOURCES =  leveldb/port/port_posix_sse.cc

src/Makefile.qt.include

@@ -407,7 +407,7 @@ endif
 if ENABLE_ZMQ
 qt_bitcoin_qt_LDADD += $(LIBBITCOIN_ZMQ) $(ZMQ_LIBS)
 endif
-qt_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
+qt_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBLEVELDB_SSE42) $(LIBMEMENV) \
   $(BOOST_LIBS) $(QT_LIBS) $(QT_DBUS_LIBS) $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1) \
   $(EVENT_PTHREADS_LIBS) $(EVENT_LIBS)
 qt_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)

src/Makefile.qttest.include

@@ -60,7 +60,7 @@ if ENABLE_ZMQ
 qt_test_test_bitcoin_qt_LDADD += $(LIBBITCOIN_ZMQ) $(ZMQ_LIBS)
 endif
 qt_test_test_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) \
-  $(LIBMEMENV) $(BOOST_LIBS) $(QT_DBUS_LIBS) $(QT_TEST_LIBS) $(QT_LIBS) \
+  $(LIBLEVELDB_SSE42) $(LIBMEMENV) $(BOOST_LIBS) $(QT_DBUS_LIBS) $(QT_TEST_LIBS) $(QT_LIBS) \
   $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1) \
   $(EVENT_PTHREADS_LIBS) $(EVENT_LIBS)
 qt_test_test_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)

src/Makefile.test.include

@@ -96,8 +96,8 @@ endif
 
 test_test_bitcoin_SOURCES = $(BITCOIN_TESTS) $(JSON_TEST_FILES) $(RAW_TEST_FILES)
 test_test_bitcoin_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) -I$(builddir)/test/ $(TESTDEFS) $(EVENT_CFLAGS)
-test_test_bitcoin_LDADD = $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
-  $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1) $(EVENT_LIBS) $(EVENT_PTHREADS_LIBS)
+test_test_bitcoin_LDADD = $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) \
+  $(LIBLEVELDB) $(LIBLEVELDB_SSE42) $(LIBMEMENV) $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1) $(EVENT_LIBS) $(EVENT_PTHREADS_LIBS)
 test_test_bitcoin_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 if ENABLE_WALLET
 test_test_bitcoin_LDADD += $(LIBBITCOIN_WALLET)

src/leveldb/Makefile

@@ -44,6 +44,7 @@ TESTS = \
 	util/cache_test \
 	util/coding_test \
 	util/crc32c_test \
+	util/env_posix_test \
 	util/env_test \
 	util/hash_test
 
@@ -121,7 +122,7 @@ SHARED_MEMENVLIB = $(SHARED_OUTDIR)/libmemenv.a
 else
 # Update db.h if you change these.
 SHARED_VERSION_MAJOR = 1
-SHARED_VERSION_MINOR = 19
+SHARED_VERSION_MINOR = 20
 SHARED_LIB1 = libleveldb.$(PLATFORM_SHARED_EXT)
 SHARED_LIB2 = $(SHARED_LIB1).$(SHARED_VERSION_MAJOR)
 SHARED_LIB3 = $(SHARED_LIB1).$(SHARED_VERSION_MAJOR).$(SHARED_VERSION_MINOR)
@@ -337,6 +338,9 @@ $(STATIC_OUTDIR)/db_test:db/db_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS)
 $(STATIC_OUTDIR)/dbformat_test:db/dbformat_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) $(LDFLAGS) $(CXXFLAGS) db/dbformat_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
 
+$(STATIC_OUTDIR)/env_posix_test:util/env_posix_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS)
+	$(CXX) $(LDFLAGS) $(CXXFLAGS) util/env_posix_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
+
 $(STATIC_OUTDIR)/env_test:util/env_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) $(LDFLAGS) $(CXXFLAGS) util/env_test.cc $(STATIC_LIBOBJECTS) $(TESTHARNESS) -o $@ $(LIBS)
 
@@ -412,3 +416,9 @@ $(SHARED_OUTDIR)/%.o: %.cc
 
 $(SHARED_OUTDIR)/%.o: %.c
 	$(CC) $(CFLAGS) $(PLATFORM_SHARED_CFLAGS) -c $< -o $@
+
+$(STATIC_OUTDIR)/port/port_posix_sse.o: port/port_posix_sse.cc
+	$(CXX) $(CXXFLAGS) $(PLATFORM_SSEFLAGS) -c $< -o $@
+
+$(SHARED_OUTDIR)/port/port_posix_sse.o: port/port_posix_sse.cc
+	$(CXX) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(PLATFORM_SSEFLAGS) -c $< -o $@

src/leveldb/README.md

@@ -16,7 +16,7 @@ Authors: Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
   * External activity (file system operations etc.) is relayed through a virtual interface so users can customize the operating system interactions.
 
 # Documentation
-  [LevelDB library documentation](https://rawgit.com/google/leveldb/master/doc/index.html) is online and bundled with the source code.
+  [LevelDB library documentation](https://github.com/google/leveldb/blob/master/doc/index.md) is online and bundled with the source code.
 
 
 # Limitations
@@ -113,29 +113,30 @@ by the one or two disk seeks needed to fetch the data from disk.
 Write performance will be mostly unaffected by whether or not the
 working set fits in memory.
 
-    readrandom   :      16.677 micros/op;  (approximately 60,000 reads per second)
-    readseq      :       0.476 micros/op;  232.3 MB/s
-    readreverse  :       0.724 micros/op;  152.9 MB/s
+    readrandom  : 16.677 micros/op;  (approximately 60,000 reads per second)
+    readseq     :  0.476 micros/op;  232.3 MB/s
+    readreverse :  0.724 micros/op;  152.9 MB/s
 
 LevelDB compacts its underlying storage data in the background to
 improve read performance.  The results listed above were done
 immediately after a lot of random writes.  The results after
 compactions (which are usually triggered automatically) are better.
 
-    readrandom   :      11.602 micros/op;  (approximately 85,000 reads per second)
-    readseq      :       0.423 micros/op;  261.8 MB/s
-    readreverse  :       0.663 micros/op;  166.9 MB/s
+    readrandom  : 11.602 micros/op;  (approximately 85,000 reads per second)
+    readseq     :  0.423 micros/op;  261.8 MB/s
+    readreverse :  0.663 micros/op;  166.9 MB/s
 
 Some of the high cost of reads comes from repeated decompression of blocks
 read from disk.  If we supply enough cache to the leveldb so it can hold the
 uncompressed blocks in memory, the read performance improves again:
 
-    readrandom   :       9.775 micros/op;  (approximately 100,000 reads per second before compaction)
-    readrandom   :       5.215 micros/op;  (approximately 190,000 reads per second after compaction)
+    readrandom  : 9.775 micros/op;  (approximately 100,000 reads per second before compaction)
+    readrandom  : 5.215 micros/op;  (approximately 190,000 reads per second after compaction)
 
 ## Repository contents
 
-See doc/index.html for more explanation. See doc/impl.html for a brief overview of the implementation.
+See [doc/index.md](doc/index.md) for more explanation. See
+[doc/impl.md](doc/impl.md) for a brief overview of the implementation.
 
 The public interface is in include/*.h.  Callers should not include or
 rely on the details of any other header files in this package.  Those
@@ -148,7 +149,7 @@ Guide to header files:
 * **include/options.h**: Control over the behavior of an entire database,
 and also control over the behavior of individual reads and writes.
 
-* **include/comparator.h**: Abstraction for user-specified comparison function. 
+* **include/comparator.h**: Abstraction for user-specified comparison function.
 If you want just bytewise comparison of keys, you can use the default
 comparator, but clients can write their own comparator implementations if they
 want custom ordering (e.g. to handle different character encodings, etc.)
@@ -165,7 +166,7 @@ length into some other byte array.
 * **include/status.h**: Status is returned from many of the public interfaces
 and is used to report success and various kinds of errors.
 
-* **include/env.h**: 
+* **include/env.h**:
 Abstraction of the OS environment.  A posix implementation of this interface is
 in util/env_posix.cc
 

src/leveldb/build_detect_platform

@@ -63,6 +63,7 @@ PLATFORM_SHARED_EXT="so"
 PLATFORM_SHARED_LDFLAGS="-shared -Wl,-soname -Wl,"
 PLATFORM_SHARED_CFLAGS="-fPIC"
 PLATFORM_SHARED_VERSIONED=true
+PLATFORM_SSEFLAGS=
 
 MEMCMP_FLAG=
 if [ "$CXX" = "g++" ]; then
@@ -77,6 +78,7 @@ case "$TARGET_OS" in
         COMMON_FLAGS="$MEMCMP_FLAG -lpthread -DOS_LINUX -DCYGWIN"
         PLATFORM_LDFLAGS="-lpthread"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     Darwin)
         PLATFORM=OS_MACOSX
@@ -85,24 +87,28 @@ case "$TARGET_OS" in
         [ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
         PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name $INSTALL_PATH/"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     Linux)
         PLATFORM=OS_LINUX
         COMMON_FLAGS="$MEMCMP_FLAG -pthread -DOS_LINUX"
         PLATFORM_LDFLAGS="-pthread"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     SunOS)
         PLATFORM=OS_SOLARIS
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_SOLARIS"
         PLATFORM_LIBS="-lpthread -lrt"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     FreeBSD)
         PLATFORM=OS_FREEBSD
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_FREEBSD"
         PLATFORM_LIBS="-lpthread"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     GNU/kFreeBSD)
         PLATFORM=OS_KFREEBSD
@@ -115,31 +121,36 @@ case "$TARGET_OS" in
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_NETBSD"
         PLATFORM_LIBS="-lpthread -lgcc_s"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     OpenBSD)
         PLATFORM=OS_OPENBSD
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_OPENBSD"
         PLATFORM_LDFLAGS="-pthread"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     DragonFly)
         PLATFORM=OS_DRAGONFLYBSD
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_DRAGONFLYBSD"
         PLATFORM_LIBS="-lpthread"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         ;;
     OS_ANDROID_CROSSCOMPILE)
         PLATFORM=OS_ANDROID
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_ANDROID -DLEVELDB_PLATFORM_POSIX"
         PLATFORM_LDFLAGS=""  # All pthread features are in the Android C library
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         CROSS_COMPILE=true
         ;;
     HP-UX)
         PLATFORM=OS_HPUX
         COMMON_FLAGS="$MEMCMP_FLAG -D_REENTRANT -DOS_HPUX"
         PLATFORM_LDFLAGS="-pthread"
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         # man ld: +h internal_name
         PLATFORM_SHARED_LDFLAGS="-shared -Wl,+h -Wl,"
         ;;
@@ -148,6 +159,7 @@ case "$TARGET_OS" in
         COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"
         [ -z "$INSTALL_PATH" ] && INSTALL_PATH=`pwd`
         PORT_FILE=port/port_posix.cc
+        PORT_SSE_FILE=port/port_posix_sse.cc
         PLATFORM_SHARED_EXT=
         PLATFORM_SHARED_LDFLAGS=
         PLATFORM_SHARED_CFLAGS=
@@ -182,7 +194,7 @@ set +f # re-enable globbing
 
 # The sources consist of the portable files, plus the platform-specific port
 # file.
-echo "SOURCES=$PORTABLE_FILES $PORT_FILE" >> $OUTPUT
+echo "SOURCES=$PORTABLE_FILES $PORT_FILE $PORT_SSE_FILE" >> $OUTPUT
 echo "MEMENV_SOURCES=helpers/memenv/memenv.cc" >> $OUTPUT
 
 if [ "$CROSS_COMPILE" = "true" ]; then
@@ -213,6 +225,21 @@ EOF
     fi
 
     rm -f $CXXOUTPUT 2>/dev/null
+
+    # Test if gcc SSE 4.2 is supported
+    $CXX $CXXFLAGS -x c++ - -o $CXXOUTPUT -msse4.2 2>/dev/null  <<EOF
+      int main() {}
+EOF
+    if [ "$?" = 0 ]; then
+        PLATFORM_SSEFLAGS="-msse4.2"
+    fi
+
+    rm -f $CXXOUTPUT 2>/dev/null
+fi
+
+# Use the SSE 4.2 CRC32C intrinsics iff runtime checks indicate compiler supports them.
+if [ -n "$PLATFORM_SSEFLAGS" ]; then
+    PLATFORM_SSEFLAGS="$PLATFORM_SSEFLAGS -DLEVELDB_PLATFORM_POSIX_SSE"
 fi
 
 PLATFORM_CCFLAGS="$PLATFORM_CCFLAGS $COMMON_FLAGS"
@@ -225,6 +252,7 @@ echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> $OUTPUT
 echo "PLATFORM_LIBS=$PLATFORM_LIBS" >> $OUTPUT
 echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> $OUTPUT
 echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> $OUTPUT
+echo "PLATFORM_SSEFLAGS=$PLATFORM_SSEFLAGS" >> $OUTPUT
 echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> $OUTPUT
 echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> $OUTPUT
 echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> $OUTPUT