lzma: Add Kconfig options to optimize for size

Currently, our LZMA library has an option for optimizing for size,
rather than speed. It is a minimal savings today, and has not been worth
enabling. As this will change in the near future, add options now to
allow disabling it in full U-Boot or in SPL, and enable these on
gardena-smart-gateway-mt7688 which is very close to the size limit
today.

Reviewed-by: Stefan Roese <stefan.roese@mailbox.org>
Signed-off-by: Tom Rini <trini@konsulko.com>

configs/gardena-smart-gateway-mt7688_defconfig

@@ -101,4 +101,6 @@ CONFIG_MT7621_SPI=y
 CONFIG_WDT=y
 CONFIG_WDT_MT7621=y
 CONFIG_LZMA=y
+CONFIG_LZMA_SIZE_OPTIMIZATION=y
 CONFIG_SPL_LZMA=y
+CONFIG_SPL_LZMA_SIZE_OPTIMIZATION=y

lib/Kconfig

@@ -838,6 +838,13 @@ config LZMA
 	  ratio and fairly fast decompression speed. See also
 	  CONFIG_CMD_LZMADEC which provides a decode command.
 
+config LZMA_SIZE_OPTIMIZATION
+	bool "Optimize the LZMA algorithm for smaller binary size"
+	help
+	  This enables building the LZMA library optimized for size, rather
+	  than performance. This can be a loss of 15-20% in decompression
+	  speed, but a savings of close to two kilobytes in many cases.
+
 config LZO
 	bool "Enable LZO decompression support"
 	help
@@ -932,6 +939,13 @@ config SPL_LZMA
 	help
 	  This enables support for LZMA compression algorithm for SPL boot.
 
+config SPL_LZMA_SIZE_OPTIMIZATION
+	bool "Optimize the LZMA algorithm for smaller binary size in SPL"
+	help
+	  This enables building the LZMA library optimized for size, rather
+	  than performance. This can be a loss of 15-20% in decompression
+	  speed, but a savings of close to two kilobytes in many cases.
+
 config TPL_LZMA
 	bool "Enable LZMA decompression support for TPL build"
 	depends on TPL

lib/lzma/Makefile

@@ -7,5 +7,6 @@
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
 ccflags-y += -D_LZMA_PROB32
+ccflags-$(CONFIG_$(PHASE_)LZMA_SIZE_OPTIMIZATION) += -D_LZMA_SIZE_OPT
 
 obj-y += LzmaDec.o LzmaTools.o