Excerpt from http://www.mingw.org/wiki/FAQ:
What's the difference between make and mingw32-make?
The "native" (i.e.: MSVCRT dependent) port of make is lacking in some functionality and has modified functionality due to the lack of POSIX on Win32. There also exists a version of make in the MSYS distribution that is dependent on the MSYS runtime. This port operates more as make was intended to operate and gives less headaches during execution. Based on this, the MinGW developers/maintainers/packagers decided it would be best to rename the native version so that both the "native" version and the MSYS version could be present at the same time without file name collision.
So,look into C:\MinGW\bin directory and first make sure what make executable, have you installed.(make.exe or mingw32-make.exe)
Before using MinGW, you should add C:\MinGW\bin; to the PATH environment variable using the instructions mentioned at http://www.mingw.org/wiki/Getting_Started/
Then cd to your directory, where you have the makefile and Try using mingw32-make.exe makefile.in
or simply make.exe makefile.in
(depending on executables in C:\MinGW\bin).
If you want a GUI based solution, install DevCPP IDE and then re-make.