make buildwotrld can not find zlib,h

[Dmitry Luhtionov]

c++  -O2 -pipe
-I/usr/src/lib/clang/libllvmsupport/../../../contrib/llvm/include
-I/usr/src/lib/clang/libllvmsupport/../../../contrib/llvm/tools/clang/include
-I/usr/src/lib/clang/libllvmsupport/../../../contrib/llvm/lib/Support -I.
-I/usr/src/lib/clang/libllvmsupport/../../../contrib/llvm/../../lib/clang/include
-DLLVM_ON_UNIX -DLLVM_ON_FREEBSD -D__STDC_LIMIT_MACROS
-D__STDC_CONSTANT_MACROS -DNDEBUG -fno-strict-aliasing
-DLLVM_DEFAULT_TARGET_TRIPLE=\"x86_64-unknown-freebsd11.0\"
-DLLVM_HOST_TRIPLE=\"x86_64-unknown-freebsd11.0\"
-DDEFAULT_SYSROOT=\"/usr/obj/usr/src/tmp\" -MD -MF.depend.Compression.o
-MTCompression.o -Qunused-arguments
-I/usr/obj/usr/src/tmp/legacy/usr/include  -std=c++11 -fno-exceptions
-fno-rtti -stdlib=libc++ -Wno-c++11-extensions  -c
/usr/src/lib/clang/libllvmsupport/../../../contrib/llvm/lib/Support/Compression.cpp
-o Compression.o
/usr/src/lib/clang/libllvmsupport/../../../contrib/llvm/lib/Support/Compression.cpp:21:10:
fatal error: 'zlib.h' file not found
#include <zlib.h>
         ^
1 error generated.