mtmd: use sha256 for input hashing (#27274)

* mtmd: use sha256 for input hashing

* void conflict with boringssl

vendor/hash/CMakeLists.txt

@@ -4,18 +4,30 @@ llama_add_compile_flags()
 
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
-add_library(${TARGET} STATIC
+set(VENDOR_SRCS
     xxhash/xxhash.c
     sha1/sha1.c
     sha256/sha256.c
 )
 
-# disable warnings in 3rd party code
+add_library(${TARGET} STATIC
+    hash.cpp
+    hash.h
+    ${VENDOR_SRCS}
+)
+
+target_compile_features(${TARGET} PRIVATE cxx_std_17)
+
+# disable warnings in 3rd party code, but keep them for hash.cpp
 if (CMAKE_C_COMPILER_ID STREQUAL "MSVC")
-    target_compile_options(${TARGET} PRIVATE /w)
+    set(NO_WARN_FLAG /w)
 else()
-    target_compile_options(${TARGET} PRIVATE -w)
+    set(NO_WARN_FLAG -w)
 endif()
+set_source_files_properties(${VENDOR_SRCS} PROPERTIES COMPILE_OPTIONS ${NO_WARN_FLAG})
+
+# sha1 lives in a namespace to avoid a clash with boringssl, see scripts/sync_vendor.py
+set_source_files_properties(sha1/sha1.c PROPERTIES LANGUAGE CXX)
 
 # sha256.c includes "rotate-bits/rotate-bits.h", so consumers get this dir too
 target_include_directories(${TARGET} PUBLIC .)