Fix failing build on Cygwin with CS toolchain

Problem: On Cygwin, CodeSourcery toolchain doesn't use the header files from
the 'current' directory, but instead picks the header files from the
 directory where the C file resides, hence this workaround

Signed-off-by: Kedar Sovani <kedars@marvell.com>
Signed-off-by: Hrishikesh Dhayagude <dhrishi@marvell.com>
Fix dep files on Cygwin

Problem: Toolchains create files with c:\, whereas, Cygwin requires /cygdrive/c/

Signed-off-by: Kedar Sovani <kedars@marvell.com>
Signed-off-by: Hrishikesh Dhayagude <dhrishi@marvell.com>