Using GSL on Windows (compiling, linking, ect). A Step by Step Guide
You need to put the test.c before the libraries. Libraries should be specified on the command line after the things that use the symbols in them, so change to:
gcc test.c -Wall -I"C:\Users\Rohan\Desktop\GnuWin32\include" -L"C:\Users\Rohan\Desktop\GnuWin32\lib" -lgslcblas -lgsl -lm -o test ^^^^^^ (put this first)