C2NASM
Uses gcc and objconv to convert a C program to nasm.
To use it, give execution permission to c2nasm.sh and then:
./c2nasm.sh <sourcefile.c>
The result will be a .nasm file with the nasm, and a .run file which is the executable.
Note that you might get a better nasm output by tunning the optimization parameter in gcc (-O0 for no optimization, -O3 to optimize as much as possible).
Based on the question: http://stackoverflow.com/questions/20737947/how-to-generate-a-nasm-compilable-assembly-code-from-c-source-code-on-linux/