What are advantages of using Sepples?

1.templates are easily replaced by macros and _Generic (which selects arguments by compile-time type(without any float/int promotions!)
2.function overload is replaced by above as well.
3.Classes are essentially structs with function pointers.
GCC supports constructors(attribute constructor) and destructors(attribute cleanup) in plain C
http://stackoverflow.com/questions/1113409/attribute-constructor-equivalent-in-vc
http://echorand.me/site/notes/articles/c_cleanup/cleanup_attribute_c.html
4.constexpr can be rewritten as expression macros ({macro;return var;}) which will be optimized via constant propogation(but unlike constexpr can be runtime dependent).
5.GCC has new apply function for plain C
https://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing-Calls
6.Thread-safe atomics built-ins in Plain C
https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html#g_t_005f_005fatomic-Builtins

>>35
There's also Pelles C/LCC and TCC. Both are C only. I don't have much experience with the former, but it's said to support up to C11. The latter supports C99, compiles very fast, and produces very small binaries (2KB for Hello World, compared to 16KB in GCC and 32KB in MSVC) but at the expense of optimization, and has some bugs (e.g. generates faulty code for returning structs from functions) and is no longer under active development.