I'm looking for a good collection of libraries for ANSI-C, stuff for handling vectors, hash maps, binary tress, string processing, etc.
Try glib? It's used by GTK+, but it can also be used on other platforms. You can also try Apache APR, which is used by the Apache web server and some of their other C components, or NSPR, which is used by Mozilla projects in C.
gnu's glib collection. furthermore, it's portable for many platforms.
You might also find this question useful:
Container Class / Library for C
As well, this book might be interesting:
The full source code is on the CD and it has code for most of those data structures and algorithms.
check also gnulib's data structures. This library also provides many other features as well as portable layer to ANSI/non-ANSI compilers and POSIX/non-POSIX systems.
GLUT OpenGL I can recommend for very flexible C (graphics) development
来源：https://stackoverflow.com/questions/1588385/good-collection-of-libraries-for-c