编译vsftpd有点不明白，请高手指点。

kaemnt

为什么我编译vsftpd时候提示错误什么的，但安装上一切都正常使用。
2.0.3和2.0.4都一样。请高手指点。
下面是编译时候的信息
gcc -c main.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c utility.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c prelogin.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c ftpcmdio.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c postlogin.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c privsock.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c tunables.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c ftpdataio.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c secbuf.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c ls.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c postprivparent.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c logging.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c str.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
str.c: 在函数 ‘str_iconv_write’ 中：
str.c:678: 警告：assignment discards qualifiers from pointer target type
str.c:676: 警告：未使用的变量 ‘print_buf’
str.c: 在函数 ‘str_iconv_read’ 中：
str.c:753: 警告：assignment discards qualifiers from pointer target type
str.c:751: 警告：未使用的变量 ‘print_buf’
str.c: 在函数 ‘str_locate_text_reverse’ 中：
str.c:496: 警告：‘retval.char_found’ is used uninitialized in this function
str.c: 在函数 ‘str_locate_text’ 中：
str.c:471: 警告：‘retval.char_found’ is used uninitialized in this function
str.c: 在函数 ‘str_locate_chars’ 中：
str.c:457: 警告：‘retval.char_found’ is used uninitialized in this function
str.c:457: 警告：‘retval.index’ is used uninitialized in this function
gcc -c netstr.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c sysstr.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c strlist.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c banner.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c filestr.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c parseconf.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c secutil.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c ascii.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c oneprocess.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c twoprocess.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c privops.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c standalone.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c hash.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c tcpwrap.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c ipaddrparse.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
ipaddrparse.c: 在函数 ‘vsf_sysutil_parse_ipv6’ 中：
ipaddrparse.c:58: 警告：返回指针时目标与指针有/无符号不一致
gcc -c access.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c features.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c readwrite.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
readwrite.c: 在函数 ‘ftp_write_str’ 中：
readwrite.c:26: 警告：passing argument 1 of ‘str_iconv_write’ discards qualifiers from pointer target type
gcc -c ssl.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -c sysutil.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
sysutil.c: 在函数 ‘vsf_sysutil_connect_timeout’ 中：
sysutil.c:1745: 警告：传递参数 5 (属于 ‘getsockopt’) 给指针时目标与指针有/无符号不一致
sysutil.c: 在函数 ‘vsf_sysutil_iconv_init_read’ 中：
sysutil.c:2647: 警告：passing argument 1 of ‘vsf_sysutil_free’ discards qualifiers from pointer target type
sysutil.c:2649: 警告：passing argument 1 of ‘vsf_sysutil_free’ discards qualifiers from pointer target type
sysutil.c: 在函数 ‘vsf_sysutil_iconv_init_write’ 中：
sysutil.c:2671: 警告：passing argument 1 of ‘vsf_sysutil_free’ discards qualifiers from pointer target type
sysutil.c:2673: 警告：passing argument 1 of ‘vsf_sysutil_free’ discards qualifiers from pointer target type
gcc -c sysdeputil.c -O2 -Wall -W -Wshadow  -idirafter dummyinc
gcc -o vsftpd main.o utility.o prelogin.o ftpcmdio.o postlogin.o privsock.o tunables.o ftpdataio.o secbuf.o ls.o postprivparent.o logging.o str.o netstr.o sysstr.o strlist.o banner.o filestr.o parseconf.o secutil.o ascii.o oneprocess.o twoprocess.o privops.o standalone.o hash.o tcpwrap.o ipaddrparse.o access.o features.o readwrite.o ssl.o sysutil.o sysdeputil.o -Wl,-s `./vsf_findlibs.sh`