Hashmap improvements in grow and re-hash

Better hashmap grow and rehash behaviour. Now the hashmap tracks the number of tombstones
in the hashmap, and triggers a re-hash if it exceeds the threshold. Same things happens
with the number of actual entries, but instead of only re-hashing it grows by doubling
and only then re-hashes.

Author: bamless

Makefile

@@ -1,4 +1,6 @@
-CFLAGS  ?= -Wall -Wextra -Wno-override-init -std=c99 -ggdb
+# CC = clang
+CFLAGS  ?= -Wall -Wextra -Wstrict-aliasing=2 -Wno-override-init -std=c99 -ggdb
+# -fsanitize=address,undefined -fno-sanitize-recover=all -fno-omit-frame-pointer -fno-optimize-sibling-calls
 LDFLAGS ?=
 
 .PHONY: all

README.md

@@ -31,15 +31,15 @@ Features:
 > library headers to disable names without prefixes.
 
  Configuration options:
- ```c
+```c
 #define EXTLIB_NO_SHORTHANDS  // Disable shorthands names, only prefixed one will be defined
 #define EXTLIB_NO_STD         // Do not use libc functions
 #define EXTLIB_WASM           // Enable when compiling for wasm target. Implies EXTLIB_NO_STD
 #define EXTLIB_THREADSAFE     // Thread safe Context
 #define EXTLIB_SHARED_EXPORT  // Mark all public API symbols for shared library use (see below)
 #define NDEBUG                // Strips runtime assertions and replaces unreachables with compiler
                               // intrinsics
- ```
+```
 
 ### Building as a shared library