However when compiling the source i got the following error. I have included header files which are on "/usr/include".
make -f /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/Rules.mk /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/common/symbols-dummy.o
make[4]: Entering directory `/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86'
gcc -O2 -fomit-frame-pointer -m64 -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement -DNDEBUG -nostdinc -fno-builtin -fno-common -iwithprefix include -Werror -Wno-pointer-arith -pipe -I/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/include -I/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/include/asm-x86/mach-generic -I/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/include/asm-x86/mach-default -I/usr/include -msoft-float -fno-stack-protector -fno-exceptions -mno-red-zone -fpic -fno-asynchronous-unwind-tables -DGCC_HAS_VISIBILITY_ATTRIBUTE -g -D__XEN__ -MMD -MF .symbols-dummy.o.d -c /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/common/symbols-dummy.c -o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/common/symbols-dummy.o
make[4]: Leaving directory `/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86'
ld -melf_x86_64 -L/usr/include -L/usr/include/ -T xen.lds -N /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86/boot/built_in.o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/common/built_in.o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/drivers/built_in.o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/xsm/built_in.o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86/built_in.o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/crypto/built_in.o \
/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/common/symbols-dummy.o -o /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/.xen-syms.0
/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86/built_in.o: In function `mem_sharing_nominate_page':
/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86/mm/mem_sharing.c:517: undefined reference to `fopen'
/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86/mm/mem_sharing.c:517: relocation truncated to fit: R_X86_64_PC32 against undefined symbol `fopen'
ld: /home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/.xen-syms.0: hidden symbol `fopen' isn't defined
ld: final link failed: Nonrepresentable section on output
make[3]: *** [/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/xen-syms] Error 1
make[3]: Leaving directory `/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/arch/x86'
make[2]: *** [/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen/xen] Error 2
make[2]: Leaving directory `/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen'
make[1]: *** [install] Error 2
make[1]: Leaving directory `/home/thilakshi/Xen/Xen-4.2/xen-4.0-testing.hg/xen'
make: *** [install-xen] Error 2
Thanks.