docs: update strbuf and added xalloc.

docs/strbuf.txt

@@ -55,6 +55,10 @@ strbuf_squeeze():
 
 Squeezes "together" sequences of 'ch' into one character.
 
+strbuf_term():
+
+ensure the string is terminated with 'ch'. will not change the string if it is already terminated.
+
 strbuf_release():
 
 This function should be used to detach the ->buf member from the strbuf_t structure.

docs/xalloc.txt

@@ -0,0 +1,37 @@
+-----------------------------------
+  xalloc - safe memory allocation
+-----------------------------------
+
+this module implements malloc and friends + some extensions.
+if __DEBUG__ symbol is defined. the functions will provide extended
+debug logic and kills the program (passing 0 as size to malloc for example).
+
+the funtions will at all times kill the program if memory can't be allocated for
+some reason, this makes the need for client-code to check for null pointers returned
+by these functions redundant.
+
+-- functions
+
+xmalloc():
+
+    just like malloc, this function allocates a block of memory of 'size' bytes.
+    if compiled with the __DEBUG__ symbol, the function will not allow zero size
+
+xmallocz():
+
+    exactly like xmalloc but will initialize the block with zero.
+
+xrealloc():
+
+    reallocates a previous allocated block of memory to 'size' bytes.
+    if compiled with the __DEBUG__ symbol, the function will not allow zero size
+
+xstrdup():
+
+    allocates and copies the string 's' to a new memory location and returns it to the user.
+    if compiled with the __DEBUG__ symbol, the function will not allow 's' to be a NULL pointer
+
+xfree():
+
+    free's a previous allocated block pointed by 'ptr' that is allocated by xmalloc/malloc.
+    if compiled with the __DEBUG__ symbol, the function will not allow 'ptr' to be a NULL pointer