diff --git a/core/Makefile b/core/Makefile
index cc54836..f7f6e48 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -114,7 +114,7 @@
   ifneq ($(filter eng.%,$(BUILD_NUMBER)),)
     # Trim down BUILD_FINGERPRINT: the default BUILD_NUMBER makes it easily exceed
     # the Android system property length limit (PROPERTY_VALUE_MAX=92).
-    BF_BUILD_NUMBER := $(USER)$(shell date -d "$(BUILD_DATETIME)" +%m%d%H%M)
+    BF_BUILD_NUMBER := $(USER)$(shell date +%m%d%H%M)
   else
     BF_BUILD_NUMBER := $(BUILD_NUMBER)
   endif
@@ -197,7 +197,6 @@
 			PRIVATE_BUILD_DESC="$(PRIVATE_BUILD_DESC)" \
 			BUILD_ID="$(BUILD_ID)" \
 			BUILD_DISPLAY_ID="$(BUILD_DISPLAY_ID)" \
-			BUILD_DATETIME="$(BUILD_DATETIME_FROM_FILE)" \
 			BUILD_NUMBER="$(BUILD_NUMBER_FROM_FILE)" \
 			BOARD_BUILD_SYSTEM_ROOT_IMAGE="$(BOARD_BUILD_SYSTEM_ROOT_IMAGE)" \
 			PLATFORM_VERSION="$(PLATFORM_VERSION)" \
@@ -247,8 +246,8 @@
 	@echo Target vendor buildinfo: $@
 	@mkdir -p $(dir $@)
 	$(hide) echo > $@
-	$(hide) echo ro.vendor.build.date=`date -d "$(BUILD_DATETIME_FROM_FILE)"`>>$@
-	$(hide) echo ro.vendor.build.date.utc=`date -d "$(BUILD_DATETIME_FROM_FILE)" +%s`>>$@
+	$(hide) echo ro.vendor.build.date=`date`>>$@
+	$(hide) echo ro.vendor.build.date.utc=`date +%s`>>$@
 	$(hide) echo ro.vendor.build.fingerprint="$(BUILD_FINGERPRINT_FROM_FILE)">>$@
 endif
 
@@ -263,8 +262,8 @@
 	@echo Target bootimage buildinfo: $@
 	@mkdir -p $(dir $@)
 	$(hide) echo > $@
-	$(hide) echo ro.bootimage.build.date=`date -d "$(BUILD_DATETIME_FROM_FILE)"`>>$@
-	$(hide) echo ro.bootimage.build.date.utc=`date -d "$(BUILD_DATETIME_FROM_FILE)" +%s`>>$@
+	$(hide) echo ro.bootimage.build.date=`date`>>$@
+	$(hide) echo ro.bootimage.build.date.utc=`date +%s`>>$@
 	$(hide) echo ro.bootimage.build.fingerprint="$(BUILD_FINGERPRINT_FROM_FILE)">>$@
 
 # -----------------------------------------------------------------
diff --git a/core/config.mk b/core/config.mk
index 3b31f80..fec018b 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -161,23 +161,6 @@
 # are specific to the user's build configuration.
 include $(BUILD_SYSTEM)/envsetup.mk
 
-# ---------------------------------------------------------------
-# Allow the C/C++ macros __DATE__ and __TIME__ to be set to the
-# build date and time, so that a build may be repeated.
-# Write the date and time to a file so that the command line
-# doesn't change every time, which would cause ninja to rebuild
-# the files.
-$(shell mkdir -p $(OUT_DIR) && \
-    date -d "$(BUILD_DATETIME)" "+%b %_d %Y" > $(OUT_DIR)/build_c_date.txt && \
-    date -d "$(BUILD_DATETIME)" +%T > $(OUT_DIR)/build_c_time.txt)
-BUILD_DATETIME_C_DATE := $$(cat $(OUT_DIR)/build_c_date.txt)
-BUILD_DATETIME_C_TIME := $$(cat $(OUT_DIR)/build_c_time.txt)
-
-ifeq ($(OVERRIDE_C_DATE_TIME),true)
-COMMON_GLOBAL_CFLAGS += -Wno-builtin-macro-redefined -D__DATE__="\"$(BUILD_DATETIME_C_DATE)\"" -D__TIME__=\"$(BUILD_DATETIME_C_TIME)\"
-COMMON_GLOBAL_CPPFLAGS += -Wno-builtin-macro-redefined -D__DATE__="\"$(BUILD_DATETIME_C_DATE)\"" -D__TIME__=\"$(BUILD_DATETIME_C_TIME)\"
-endif
-
 # The build system exposes several variables for where to find the kernel
 # headers:
 #   TARGET_DEVICE_KERNEL_HEADERS is automatically created for the current
diff --git a/core/droiddoc.mk b/core/droiddoc.mk
index 37eade6..417d4fd 100644
--- a/core/droiddoc.mk
+++ b/core/droiddoc.mk
@@ -132,7 +132,7 @@
 
 $(full_target): PRIVATE_DOCLETPATH := $(HOST_OUT_JAVA_LIBRARIES)/jsilver$(COMMON_JAVA_PACKAGE_SUFFIX):$(HOST_OUT_JAVA_LIBRARIES)/doclava$(COMMON_JAVA_PACKAGE_SUFFIX)
 $(full_target): PRIVATE_CURRENT_BUILD := -hdf page.build $(BUILD_ID)-$(BUILD_NUMBER_FROM_FILE)
-$(full_target): PRIVATE_CURRENT_TIME :=  -hdf page.now "$$(date -d "$(BUILD_DATETIME_FROM_FILE)" "+%d %b %Y %k:%M")"
+$(full_target): PRIVATE_CURRENT_TIME :=  -hdf page.now "$$(date "+%d %b %Y %k:%M")"
 $(full_target): PRIVATE_CUSTOM_TEMPLATE_DIR := $(LOCAL_DROIDDOC_CUSTOM_TEMPLATE_DIR)
 $(full_target): PRIVATE_IN_CUSTOM_ASSET_DIR := $(LOCAL_DROIDDOC_CUSTOM_TEMPLATE_DIR)/$(LOCAL_DROIDDOC_CUSTOM_ASSET_DIR)
 $(full_target): PRIVATE_OUT_ASSET_DIR := $(out_dir)/$(LOCAL_DROIDDOC_ASSET_DIR)
diff --git a/core/main.mk b/core/main.mk
index 87bcd13..b290ce1 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -102,11 +102,8 @@
 # Write the build number to a file so it can be read back in
 # without changing the command line every time.  Avoids rebuilds
 # when using ninja.
-$(shell mkdir -p $(OUT_DIR) && \
-    echo -n $(BUILD_NUMBER) > $(OUT_DIR)/build_number.txt && \
-    echo -n "$(BUILD_DATETIME)" > $(OUT_DIR)/build_date.txt)
+$(shell mkdir -p $(OUT_DIR) && echo -n $(BUILD_NUMBER) > $(OUT_DIR)/build_number.txt)
 BUILD_NUMBER_FROM_FILE := $$(cat $(OUT_DIR)/build_number.txt)
-BUILD_DATETIME_FROM_FILE := $$(cat $(OUT_DIR)/build_date.txt)
 
 # CTS-specific config.
 -include cts/build/config.mk
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 9b2ecf2..f3b2297 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -24,7 +24,6 @@
 #     DEFAULT_APP_TARGET_SDK
 #     BUILD_ID
 #     BUILD_NUMBER
-#     BUILD_DATETIME
 #
 
 # Look for an optional file containing overrides of the defaults,
@@ -90,12 +89,6 @@
   BUILD_ID := UNKNOWN
 endif
 
-ifeq "" "$(BUILD_DATETIME)"
-  # Used to reproduce builds by setting the same time. Must be in a
-  # format understood by `date`
-  BUILD_DATETIME := $(shell date)
-endif
-
 ifeq "" "$(BUILD_NUMBER)"
   # BUILD_NUMBER should be set to the source control value that
   # represents the current state of the source code.  E.g., a
@@ -106,5 +99,5 @@
   # If no BUILD_NUMBER is set, create a useful "I am an engineering build
   # from this date/time" value.  Make it start with a non-digit so that
   # anyone trying to parse it as an integer will probably get "0".
-  BUILD_NUMBER := eng.$(USER).$(shell date -d "$(BUILD_DATETIME)" +%Y%m%d.%H%M%S)
+  BUILD_NUMBER := eng.$(USER).$(shell date +%Y%m%d.%H%M%S)
 endif
diff --git a/tools/buildinfo.sh b/tools/buildinfo.sh
index 2b0ad07..1fb203a 100755
--- a/tools/buildinfo.sh
+++ b/tools/buildinfo.sh
@@ -10,8 +10,8 @@
 echo "ro.build.version.codename=$PLATFORM_VERSION_CODENAME"
 echo "ro.build.version.all_codenames=$PLATFORM_VERSION_ALL_CODENAMES"
 echo "ro.build.version.release=$PLATFORM_VERSION"
-echo "ro.build.date=`date -d \"$BUILD_DATETIME\"`"
-echo "ro.build.date.utc=`date -d \"$BUILD_DATETIME\" +%s`"
+echo "ro.build.date=`date`"
+echo "ro.build.date.utc=`date +%s`"
 echo "ro.build.type=$TARGET_BUILD_TYPE"
 echo "ro.build.user=$USER"
 echo "ro.build.host=`hostname`"