raylib libc dependency

raylib is a C library and inevitably it depends on some implementation of C standard library (libc).

While working on raylib 3.0 I took some time to analyze that dependency in detail, no plans to remove it (maybe minimize it a bit) but I think it could be useful to have the knowledge where it is required.

stdlib.h

module	libc function	raylib function
core	srand()	InitTimer()
core	abs(), rand()	GetRandomValue()
core	atexit()	InitKeyboard() InitTerminal()
shapes	fabs()	CheckCollisionCircleRec() GetCollisionRec()
utils	exit()	TraceLog()

stdio.h

Note that file loading functionality is currently being centralized to LoadFileData()/SaveFileData(), most of the file access calls below will disappear soon, replaced by memory buffers parsing (Issue #1232.

module	libc function	raylib function
text	fopen(), fseek(), fread(), fwrite(), fclose()	LoadBMFont()
text	fgets()	LoadBMFont()
textures	fopen(), fseek(), fread(), fwrite(), fclose()	ExportImageAsCode() LoadDDS() LoadPKM() LoadKTX() SaveKTX() LoadPVR() LoadASTC()
models	fopen(), fseek(), fread(), fwrite(), fclose()	LoadIQM() ExportMesh() LoadModelAnimations()
audio	fopen(), fseek(), fread(), fwrite(), fclose()	ExportWaveAsCode() LoadWAV() SaveWAV()
utils	sprintf()	TraceLog()
utils	fopen(), fseek(), fread(), fwrite(), fclose()	LoadFileData() SaveFileData()

string.h

module	libc function	raylib function
core	strlen()	GetFileNameWithoutExt() GetDirectoryPath() GetPrevDirectoryPath() OpenURL() InitEvdevInput()
core	strrchr()	GetExtension() EventThreadSpawn()
core	strcmp()	IsGamepadName() EmscriptenKeyboardCallback()
text	strcmp()	TextIsEqual()
text	strcpy()	TextAppend() TextReplace()
text	strncpy()	TextToUtf8() TextReplace()
text	strcat()	TextJoin()
text	strstr()	several funcs.
textures	strlen()	ImageTextEx()
raudio	strcmp()	IsFileExtension()

math.h

module	libc function	raylib function
models, shapes, camera	sinf(), asinf(), cosf() acosf(), sqrtf(), atan2f()	several funcs.
raymath	sinf(), cosf(), acosf(), tan() fabs(), sqrtf(), fminf(), fmaxf()	several funcs.
core	tan()	BeginMode3D()
rlgl	atan2()	SetVrConfiguration()
text	sqrtf()	GenImageFontAtlas()

stdarg.h

module	libc function	raylib function
text	va_list, va_start(), vsprintf(), va_end()	TextFormat()
utils	va_list, va_start(), vsprintf(), va_end()	TraceLog()

Considering the size of raylib, there is not much dependency on libc... that's an interesting consideration for embedded devices development where custom libc implementations could be used.