Enable and clean up compiler warnings in src (#824)

* WIP: enable and clean up warnings in src

* All warnings handled

---------

Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>

src/CMakeLists.txt

@@ -11,6 +11,32 @@ endif()
 
 # llama
 
+if (LLAMA_ALL_WARNINGS)
+    if (NOT MSVC)
+        list(APPEND WARNING_FLAGS -Wall -Wextra -Wpedantic -Wcast-qual -Wno-unused-function -Wno-sign-compare)
+        if (APPLE)
+            # shut up c99 extensions warning I get on my system due to arm_neon.h
+            list(APPEND WARNING_FLAGS -Wno-c99-extensions)
+        endif()
+        list(APPEND C_FLAGS       -Wshadow -Wstrict-prototypes -Wpointer-arith -Wmissing-prototypes
+                                  -Werror=implicit-int -Werror=implicit-function-declaration)
+        list(APPEND CXX_FLAGS     -Wmissing-declarations -Wmissing-noreturn)
+
+        list(APPEND C_FLAGS   ${WARNING_FLAGS})
+        list(APPEND CXX_FLAGS ${WARNING_FLAGS})
+
+        get_flags(${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER_VERSION})
+
+        add_compile_options("$<$<COMPILE_LANGUAGE:C>:${C_FLAGS};${GF_C_FLAGS}>"
+                            "$<$<COMPILE_LANGUAGE:CXX>:${CXX_FLAGS};${GF_CXX_FLAGS}>")
+    else()
+        # todo : msvc
+        set(C_FLAGS   "")
+        set(CXX_FLAGS "")
+    endif()
+endif()
+
+
 add_library(llama
             ../include/llama.h
             llama.cpp
@@ -34,9 +60,9 @@ add_library(llama
             unicode-data.cpp
             )
 
-target_include_directories(llama PUBLIC . ../include ../common)
+target_include_directories(llama PUBLIC . ../include)
 target_include_directories(llama PRIVATE ../ggml/src)
-target_compile_features   (llama PUBLIC cxx_std_11) # don't bump
+target_compile_features   (llama PUBLIC cxx_std_17)
 
 target_link_libraries(llama PUBLIC ggml)