Redirect emcmake calls to emconfigure.
Split clang options passed to clang, to be more concise and less messy. Start splitting C and C++ options.
Add option valid-abspath to add absolute path, which should be considered valid.
Migrate to using musl 0.9.13 libc bsearch to take advantage of compiled asm.js performance in the algorithm.
Migrate to using musl 0.9.13 libc atoi, atol and atoll for better asm.js performance.
Migrate to using musl 0.9.13 libc qsort for better asm.js performance.
Removed old library.js todo comment that has since been fixed and no longer applies.
Added musl 0.9.13 bcmp and bzero functions and migrated bcopy implementation to use musl for better asm.js performance.
Migrate to using musl 0.9.13 strspn and strcspn for better asm.js performance.
Migrate to using musl 0.9.13 stpcpy for better asm.js performance.
Migrate to using musl 0.9.13 strncat for better asm.js performance.
Migrate to using musl 0.9.13 memchr for better asm.js performance.
Migrate to using musl 0.9.13 strnlen for better asm.js performance.
Migrate to using musl 0.9.13 strstr for better asm.js performance.
Migrate to using musl 0.9.13 strchr, strrchr, index and rindex for better asm.js performance.
Migrate to using musl 0.9.13 strdup and strndup for better asm.js performace.
Migrate to using musl 0.9.13 strpbrk for better asm.js performance.
Migrate to using musl 0.9.13 strtok and strtok_r for better asm.js performance.
Fix test_strndup. The signature of strndup takes in a size_t for length, so passing -1 is equivalent to passing 0xFFFFFFFF, which means the whole string will get duplicated, and the old handwritten implementation had a bug.
Skip s_0_0.test_strndup, s_0_0.test_strstr, s_0_0.test_unistd_ttyname tests since new musl libc string functions optimize by assuming being able to alias types in load-store operations.