Update LZ4

Author: mcmilk

C/lz4/README.md

@@ -100,21 +100,45 @@ The following build macro can be selected to adjust source code behavior at comp
   passed as argument to become a compression state is suitably aligned.
   This test can be disabled if it proves flaky, by setting this value to 0.
 
-- `LZ4_USER_MEMORY_FUNCTIONS` : replace calls to `<stdlib,h>`'s `malloc()`, `calloc()` and `free()`
+- `LZ4_USER_MEMORY_FUNCTIONS` : replace calls to `<stdlib.h>`'s `malloc()`, `calloc()` and `free()`
   by user-defined functions, which must be named `LZ4_malloc()`, `LZ4_calloc()` and `LZ4_free()`.
   User functions must be available at link time.
 
 - `LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION` :
   Remove support of dynamic memory allocation.
   For more details, see description of this macro in `lib/lz4.c`.
 
+- `LZ4_STATIC_LINKING_ONLY_ENDIANNESS_INDEPENDENT_OUTPUT` : experimental feature aimed at producing the same
+  compressed output on platforms of different endianness (i.e. little-endian and big-endian).
+  Output on little-endian platforms shall remain unchanged, while big-endian platforms will start producing
+  the same output as little-endian ones. This isn't expected to impact backward- and forward-compatibility
+  in any way.
+
 - `LZ4_FREESTANDING` : by setting this build macro to 1,
   LZ4/HC removes dependencies on the C standard library,
   including allocation functions and `memmove()`, `memcpy()`, and `memset()`.
   This build macro is designed to help use LZ4/HC in restricted environments
   (embedded, bootloader, etc).
   For more details, see description of this macro in `lib/lz4.h`.
 
+- `LZ4_HEAPMODE` : Select how stateless compression functions like `LZ4_compress_default()`
+  allocate memory for their hash table,
+  in memory stack (0:default, fastest), or in memory heap (1:requires malloc()).
+
+- `LZ4HC_HEAPMODE` :  Select how stateless HC compression functions like `LZ4_compress_HC()`
+  allocate memory for their workspace:
+  in stack (0), or in heap (1:default).
+  Since workspace is rather large, stack can be inconvenient, hence heap mode is recommended.
+
+- `LZ4F_HEAPMODE` : selects how `LZ4F_compressFrame()` allocates the compression state,
+  either on stack (default, value 0) or using heap memory (value 1).
+
+
+#### Makefile variables
+
+The following `Makefile` variables can be selected to alter the profile of produced binaries :
+- `BUILD_SHARED` : generate `liblz4` dynamic library (enabled by default)
+- `BUILD_STATIC` : generate `liblz4` static library (enabled by default)
 
 
 #### Amalgamation