First of all allow me some comments:

Your program is not compiled and linked by Eclipse.

Compiling is done by the compiler (gcc using option -c):

make all 
Building file: ../zip.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"zip.d" -MT"zip.d" -o "zip.o" "../zip.c"
Finished building: ../zip.c

Linking is done by the linker (via the compiler using option -o):

Invoking: GCC C Linker
gcc  -o "unzipper"  ./zip.o   
./main.o: In function `zip':
/home/alk/workspace/unzipper/Debug/../zip.c:20: undefined reference to `zip_open'
/home/alk/workspace/unzipper/Debug/../zip.c:27: undefined reference to `zip_get_num_files'
/home/alk/workspace/unzipper/Debug/../zip.c:33: undefined reference to `zip_fopen_index'
/home/alk/workspace/unzipper/Debug/../zip.c:35: undefined reference to `zip_fread'
/home/alk/workspace/unzipper/Debug/../zip.c:38: undefined reference to `zip_fclose'
/home/alk/workspace/unzipper/Debug/../zip.c:43: undefined reference to `zip_close'
collect2: ld returned 1 exit status

Eclipse provides a framework helping you in managing all sources and their references as also spawing compiler and linker tasks and setting their options.

When the linker told you there where undefined references to the zip_*function during the build of your program, the cause for this was, you were missing to tell the linker (via the compiler, via Eclipse) where those zip_* functions could be found.

Those zip_* functions are located in a library, namely libzip.

So what you as the programmer need to tell the linker (via the compiler, via Eclipse) is to link those functions against what the compiler compiled from your sources.

As the result the linker is able to create a runnable program from your compiled sources together with all libraries needed. Certain libraries are know to Eclipse (and therfore to the linker) by default, for example the one containing the C standard functions, namely libc.

To get things going:

1 Remove the source files you pulled from the libzip librarie's sources from your project. Those sources had been compiled into the library libzip, which you will use in your project.

2 Tell the linker (via Eclipse) to use libzip for your project.

Do so by following the steps below:

open the project's properties

click 'C/C++ General'

click 'Path and Symbols', on the left select the 'Libraries' tab, there click 'Add' and enter zip

finally click 'OK'

3 Then try to build your program:

Building target: unzipper
Invoking: GCC C Linker
gcc  -o "unzipper"  ./zip.o   -lzip
Finished building target: unzipper

(Please note additional option -lzip!)

If the developement version of 'libzip' had been installed properly before, you should be fine.

PS: unzipper was the name I used for the Eclispe project to produce the examples.

PSS: I used Eclipse Juno SR1

I had a very similar problem with unzGoToFirstFile. If you download the ZLib sources and do a simple "grep -irl unzGoToFirstFile" you'll find that these functions are not part of ZLib at all. They are however part of a contributed library called minizip found within the ZLib sources.

Add this to the ZLib CMakeLists.txt somwhere near the bottom and it will create a library called "libunzip.a" with the required unzGoToFirstFile etc functions you require. Just link your program towards that and you should be golden.

set(UNZIP_SOURCES "contrib/minizip/unzip.c"
"contrib/minizip/zip.c"
"contrib/minizip/ioapi.c")
set(UNZIP_HEADERS "contrib/minizip/unzip.h"
"contrib/minizip/zip.h"
"contrib/minizip/ioapi.h")

add_library(unzip STATIC 
"${UNZIP_SOURCES}"
"${UNZIP_HEADERS}")

target_link_libraries(unzip zlibstatic)

install(TARGETS unzip
RUNTIME DESTINATION "${INSTALL_BIN_DIR}"
ARCHIVE DESTINATION "${INSTALL_LIB_DIR}"
LIBRARY DESTINATION "${INSTALL_LIB_DIR}" )

install(FILES ${UNZIP_HEADERS} DESTINATION "${CMAKE_INSTALL_PREFIX}/include")

@FluentCoding
I only seen it here on forums. I compiled it once in linux but not tried on
Windows hence my questions to see what zlib you used.
if binary, i think its a compiler mismatch issue you are seeing.

I used
https://github.com/kuba--/zip
which is very small and easy to use/compile but
only support zip files.
But for my use case it was ok and speed and compression is super.

It looks like you haven't linked to libzip. Make sure you are infact linking to it, and that the path to the lib is in your link path.