Compiling from svn on Arch, I get this error:

lscp.y:472:24: note: in expansion of macro 'LSCPSERVER'
load_instr_args : filename SP instrument_index SP sampler_channel { $$ = LSCPSERVER->LoadInstrument($1, $3, $5); }
^
lscp.y:42:40: error: 'yyparse_param' was not declared in this scope
#define LSCPSERVER ((yyparse_param_t*) yyparse_param)->pServer
^
lscp.y:473:24: note: in expansion of macro 'LSCPSERVER'
| NON_MODAL SP filename SP instrument_in.dex SP sampler_channel { $$ = LSCPSERVER->LoadInstrument($3, $5, $7, true); }
^
lscp.y:42:40: error: 'yyparse_param' was not declared in this scope
#define LSCPSERVER ((yyparse_param_t*) yyparse_param)->pServer
^
lscp.y:476:24: note: in expansion of macro 'LSCPSERVER'
load_engine_args : engine_name SP sampler_channel { $$ = LSCPSERVER->SetEngineType($1, $3); }
^
make[3]: *** [lscpparser.lo] Error 1
make[3]: Leaving directory `/home/victor/bin/linuxsampler-svn/src/linuxsampler-build/src/network'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/home/victor/bin/linuxsampler-svn/src/linuxsampler-build/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/victor/bin/linuxsampler-svn/src/linuxsampler-build'
make: *** [all] Error 2

It is related to bison which was upgraded on Arch to 3.0.1. Downgrading it to 2.7.12 I can build Linuxsampler again. 

Sorry, I have no knowledge to suggest the fix for the code.