Genius! perl -V | grep -i largefile shows

useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    cc='/usr/sfw/bin/gcc', ccflags ='-D_REENTRANT -fno-strict-aliasing
+ -pipe -Wdeclaration-after-statement -D_LARGEFILE_SOURCE -D_FILE_OFFS
+ET_BITS=64 -DPERL_USE_SAFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_S
+AFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_S
+AFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_S
+AFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_SAFE_PUTENV -DPERL_USE_S
+AFE_PUTENV -DPERL_USE_SAFE_PUTENV',
[download]

So it does have the two things you mentioned. httpd -V says:

Server version: Apache/2.2.8 (Unix)
Server built:   Apr 24 2008 11:03:10
Server's Module Magic Number: 20051115:11
Server loaded:  APR 1.2.12, APR-Util 1.2.12
Compiled using: APR 1.2.12, APR-Util 1.2.12
Architecture:   32-bit
Server MPM:     Prefork
  threaded:     no
    forked:     yes (variable process count)
Server compiled with....
 -D APACHE_MPM_DIR="server/mpm/prefork"
 -D APR_HAS_SENDFILE
 -D APR_HAS_MMAP
 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
 -D APR_USE_FCNTL_SERIALIZE
 -D APR_USE_PTHREAD_SERIALIZE
 -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 -D APR_HAS_OTHER_CHILD
 -D AP_HAVE_RELIABLE_PIPED_LOGS
 -D DYNAMIC_MODULE_LIMIT=128
 -D HTTPD_ROOT="/opt/custom/apache"
 -D SUEXEC_BIN="/opt/custom/apache/bin/suexec"
 -D DEFAULT_PIDLOG="logs/httpd.pid"
 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
 -D DEFAULT_LOCKFILE="logs/accept.lock"
 -D DEFAULT_ERRORLOG="logs/error_log"
 -D AP_TYPES_CONFIG_FILE="conf/mime.types"
 -D SERVER_CONFIG_FILE="conf/httpd.conf"
[download]

I don't see anything similar about large file support. The os is Solaris 2.10. I don't know how to check it for large file support.