Fix handling of realloc. If realloc() fails it returns NULL, assigning
the return value of realloc() directly to the pointer without checking
for the result will lead to a memory leak in error case.
Use a temporary pointer to hold the result of realloc(). In error case
print error and exit, otherwise assign it to the pointer we want to realloc.
Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>