Makefile and errors compiling separate files from a big project

Question

I'm trying to compile a small .cpp file but running into issues since this file utilizes functions found in many other files. Basically, I cloned the ZCash repo and am currently trying to use specific files in that project to do some testing. When I compile the entire ZCash repo that I cloned everything works perfectly, but when I try to compile the files I'm working with some of them get syntax errors.

My Makefile:

CC = g++
CFLAGS = -std=c++11 -Wall -g -c 
IDIR = /home/parallels/zcash/src/
INC = -I /home/parallels/zcash/src/ -I 
/home/parallels/zcash/depends/x86_64-unknown-linux-gnu/include/
VPATH = /home/parallels/zcash/src/

all: Main.o KeyGen.o prf.o uint256.o sha256.o
    $(CC) Main.o KeyGen.o prf.o uint256.o sha256.o -o keygenerator

Main.o: Main.cpp
    $(CC) $(CFLAGS) Main.cpp $(INC)

KeyGen.o: KeyGen.cpp
    $(CC) $(CFLAGS) KeyGen.cpp $(INC)

prf.o: prf.cpp
    $(CC) $(CFLAGS) prf.cpp $(INC)

uint256.o: uint256.cpp
    $(CC) $(CFLAGS) uint256.cpp $(INC)

sha256.o: sha256.cpp
    $(CC) $(CFLAGS) sha256.cpp $(INC)

clean: 
    rm -rf *.o keygenerator

The .cpp files being compiled reference these other files:

Main.cpp:

#include "KeyGen.h"
#include "uint252.h"
#include "uint256.h"
#include <string>

KeyGen.cpp

#include "KeyGen.h"
#include "prf.h"

prf.cpp

#include "prf.h"
#include "crypto/sha256.h"

uint256.cpp

#include "uint256.h"
#include "utilstrencodings.h"
#include <stdio.h>
#include <string.h>

sha256.cpp

#include "crypto/sha256.h"
#include "crypto/common.h"
#include <string.h>
#include <stdexcept>

So, after I try to compile these files I get the following error:

g++ -std=c++11 -Wall -g -c Main.cpp -I /home/parallels/zcash/src/ -I /home/parallels/zcash/depends/x86_64-unknown-linux-gnu/include/

g++ -std=c++11 -Wall -g -c KeyGen.cpp -I /home/parallels/zcash/src/ -I /home/parallels/zcash/depends/x86_64-unknown-linux-gnu/include/

g++ -std=c++11 -Wall -g -c prf.cpp -I /home/parallels/zcash/src/ -I /home/parallels/zcash/depends/x86_64-unknown-linux-gnu/include/

g++ -std=c++11 -Wall -g -c uint256.cpp -I /home/parallels/zcash/src/ -I /home/parallels/zcash/depends/x86_64-unknown-linux-gnu/include/

g++ -std=c++11 -Wall -g -c  sha256.cpp -I /home/parallels/zcash/src/ -I /home/parallels/zcash/depends/x86_64-unknown-linux-gnu/include/

In file included from /usr/include/x86_64-linux-gnu/bits/byteswap.h:35:0,
      
from /usr/include/endian.h:60,

             from /usr/include/x86_64-linux-gnu/bits/waitstatus.h:64,

             from /usr/include/stdlib.h:42,

             from /home/parallels/zcash/src/crypto/sha256.h:9,

             from sha256.cpp:5:

/home/parallels/zcash/src/compat/endian.h:111:17: error: expected unqualified-id before ‘__extension__’

inline uint16_t htobe16(uint16_t host_16bits)
                   ^

In the offending file /home/parallels/zcash/src/compat/endian.h:111:17, htobe16 is used as follows:

#if HAVE_DECL_HTOBE16 == 0
inline uint16_t htobe16(uint16_t host_16bits) //line #111 
{
    return bswap_16(host_16bits);
}
#endif // HAVE_DECL_HTOBE16

There also exists a file: /usr/include/endian.h who references htobe16 as follows.

# include <bits/byteswap.h> //line #60 

# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define htobe16(x) __bswap_16 (x)
#  define htole16(x) (x)
#  define be16toh(x) __bswap_16 (x)
#  define le16toh(x) (x)

Note: All the .cpp file I am compiling are located in both the ZCash repo that I cloned and the new folder I created (wondering if this might be the issue).

The folder I'm currently working on contains : KeyGen.cpp

KeyGen.h

Main.cpp

Makefile

prf.cpp

prf.h

serialize.h

sha256.cpp

sha256.h

uint252.h

uint256.cpp

uint256.h

Sorry for the long post, I truly appreciate your time and would really appreciate some help!

Answer 1

The inline functions are already declared by several macros with the same name. Similar to this question: error: expected unqualified-id before ‘__extension__’ in Linux (Cent OS)

Could have to do with a unconfigured part of the slice you're building from the whole project as this Github discussion seems to indicate: https://github.com/bitcoin/bitcoin/issues/5920