diff --git a/Makefile b/Makefile
index 13062d8e7..4436aa0d6 100644
--- a/Makefile
+++ b/Makefile
@@ -9,9 +9,8 @@ INSTALL_PATH ?= $(CURDIR)
 # Uncomment exactly one of the lines labelled (A), (B), and (C) below
 # to switch between compilation modes.
 
-# OPT ?= -O2 -DNDEBUG       # (A) Production use (optimized mode)
-# OPT ?= -g2              # (B) Debug mode, w/ full line-level debugging symbols
-OPT ?= -O2 -g2 -DNDEBUG -Wall # (C) Profiling mode: opt, but w/debugging symbols
+# OPT ?= -DNDEBUG     # (A) Production use (optimized mode)
+OPT += -O3 -fno-omit-frame-pointer -momit-leaf-frame-pointer
 #-----------------------------------------------
 
 # detect what platform we're building on
@@ -19,8 +18,9 @@ $(shell ./build_detect_platform build_config.mk)
 # this file is generated by the previous line to set build flags and sources
 include build_config.mk
 
-CFLAGS += -Werror -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
-CXXFLAGS += -Werror -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT)
+WARNING_FLAGS = -Wall -Werror -Wno-unused-parameter -Wno-sign-compare
+CFLAGS += -g $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
+CXXFLAGS += -g $(WARNING_FLAGS) -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT)
 
 LDFLAGS += $(PLATFORM_LDFLAGS)
 
@@ -65,7 +65,6 @@ TOOLS = \
 
 PROGRAMS = db_bench $(TESTS) $(TOOLS)
 BENCHMARKS = db_bench_sqlite3 db_bench_tree_db
-VERSIONFILE=util/build_version.cc
 
 LIBRARY = libleveldb.a
 MEMENVLIBRARY = libmemenv.a
@@ -99,13 +98,17 @@ $(SHARED3):
 
 endif  # PLATFORM_SHARED_EXT
 
-all: $(VERSIONFILE) $(SHARED) $(LIBRARY) $(TOOLS)
+all: $(SHARED) $(LIBRARY) $(PROGRAMS)
+
+release:
+	make clean
+	OPT=-DNDEBUG make -j32
 
 check: all $(PROGRAMS) $(TESTS) $(TOOLS)
 	for t in $(TESTS); do echo "***** Running $$t"; ./$$t || exit 1; done
 
 clean:
-	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) $(THRIFTSERVER) */*.o */*/*.o ios-x86/*/*.o ios-arm/*/*.o build_config.mk $(VERSIONFILE) */*.d
+	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) $(THRIFTSERVER) */*.o */*/*.o ios-x86/*/*.o ios-arm/*/*.o build_config.mk
 	-rm -rf ios-x86/* ios-arm/*
 
 $(LIBRARY): $(LIBOBJECTS)
diff --git a/build_detect_version b/build_detect_version
index db2fca8ef..73dbf62af 100755
--- a/build_detect_version
+++ b/build_detect_version
@@ -8,7 +8,8 @@
 #
 
 # create git version file
-VFILE=util/build_version.cc
+VFILE=$(mktemp)
+trap "rm $VFILE" EXIT
 
 # check to see if git is in the path
 which git > /dev/null
@@ -19,6 +20,10 @@ else
   echo "git not found"| awk ' BEGIN {print "#include \"build_version.h\""} {print "const char * leveldb_build_git_sha = \"leveldb_build_git_sha:git not found\";"} END {}' > ${VFILE}
 fi
 
-date | awk 'BEGIN {} {print "const char * leveldb_build_git_datetime = \"leveldb_build_git_datetime:"$0"\";"} END {} ' >> ${VFILE}
 echo "const char * leveldb_build_compile_date = __DATE__;" >> ${VFILE}
 echo "const char * leveldb_build_compile_time = __TIME__;" >> ${VFILE}
+
+OUTFILE=util/build_version.cc
+if [ ! -e $OUTFILE ] || ! cmp -s $VFILE $OUTFILE; then
+    cp $VFILE $OUTFILE
+fi
diff --git a/db/db_impl.cc b/db/db_impl.cc
index 4d508517f..dc2a3650a 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -2385,8 +2385,8 @@ Status DestroyDB(const std::string& dbname, const Options& options) {
 // A global method that can dump out the build version
 void dumpLeveldbBuildVersion(Logger * log) {
   Log(log, "Git sha %s", leveldb_build_git_sha);
-  Log(log, "Git datetime %s", leveldb_build_git_datetime);
-  Log(log, "Compile time %s %s", leveldb_build_compile_time, leveldb_build_compile_date);
+  Log(log, "Compile time %s %s",
+      leveldb_build_compile_time, leveldb_build_compile_date);
 }
 
 }  // namespace leveldb
diff --git a/util/build_version.h b/util/build_version.h
index bcf869372..516c6404b 100644
--- a/util/build_version.h
+++ b/util/build_version.h
@@ -4,7 +4,6 @@
 
 // these variables tell us about the git config and time
 extern const char* leveldb_build_git_sha;
-extern const char* leveldb_build_git_datetime;
 
 // these variables tell us when the compilation occured
 extern const char* leveldb_build_compile_time;