Clean up configure/build-process.

- assume C++ standard-conforming environment
- add a user-option for gnuplot-support
- separate gnuplot-code into declaration and implementation,
  so we can define at EO-build-time whether to use it or not.

Adopt code and Makefiles to above changes.

Some minor fixes.

eo/src/utils/pipecom.cpp

@@ -0,0 +1,173 @@
+/* ----------------------------------------------------------------------
+ * Where........: CMAP - Polytechnique
+ * File.........: pipecom.c
+ * Author.......: Bertrand Lamy (Equipe genetique)
+ * Created......: Mon Mar 13 13:50:11 1995
+ * Description..: Communication par pipe bidirectionnel avec un autre process
+ * ----------------------------------------------------------------------
+ */
+
+// MSC equivalent must be written and tested or some #idef instructions added
+// with a clear message at compile time that this is for Unix only ???
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <cstdlib>
+#include <cstring>
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "pipecom.h"
+
+
+
+int Check( PCom *com )
+{
+    if( ! com ) {
+	fprintf( stderr, "PipeCom: Null pointer.\n" );
+	fflush( stderr );
+	return 0;
+    }
+    if( kill( com->pid, 0 ) != 0 ) {
+	fprintf( stderr, "PipeCom: process doesn't exists.\n" );
+	fflush( stderr );
+	return 0;
+    }
+    return 1;
+}
+
+
+PCom * PipeComOpen( char *prog )
+{
+    char	*args[2];
+    args[0] = prog;
+    args[1] = NULL;
+    return PipeComOpenArgv( prog, args );
+}
+
+
+PCom * PipeComOpenArgv( char *prog, char *argv[] )
+{
+    int		toFils[2];
+    int		toPere[2];
+    int		sonPid;
+    PCom	* ret = NULL;
+
+    if( pipe( toFils ) < 0 ) {
+	perror( "PipeComOpen: Creating pipes" );
+	return ret;
+    }
+    if( pipe( toPere ) < 0 ) {
+	perror( "PipeComOpen: Creating pipes" );
+	return ret;
+    }
+
+    switch( (sonPid = vfork()) ) {
+    case -1:
+	perror("PipeComOpen: fork failed" );
+	return ret;
+	break;
+
+    case 0:
+	/* --- Here's the son --- */
+	/* --- replace old stdin --- */
+	if( dup2( toFils[0], fileno(stdin) ) < 0 ) {
+	    perror( "PipeComOpen(son): could not connect" );
+	    exit( -1 );
+	    /* --- AVOIR: kill my father --- */
+	}
+	if( dup2( toPere[1], fileno(stdout) ) < 0 ) {
+	    perror( "PipeComOpen(son): could not connect" );
+	    exit( -1 );
+	}
+	if( execvp( prog, argv ) < 0 ) {
+	    perror( prog );
+	    perror( "PipeComOpen: can't exec" );
+	    exit(1);
+	}
+	break;
+    default:
+	ret = (PCom *) malloc( sizeof(PCom) );
+	if( ! ret )
+	    return NULL;
+
+	ret->fWrit = (FILE *)fdopen( toFils[1], "w" );
+	ret->fRead = (FILE *)fdopen( toPere[0], "r" );
+	ret->pid = sonPid;
+    }
+    return ret;
+}
+
+
+int PipeComSend( PCom *to, const char *line )
+{
+    int	nb = 0;
+    if( ! Check(to ) )
+	return nb;
+    nb = fprintf( to->fWrit, line );
+    fflush( to->fWrit );
+    return nb;
+}
+
+
+int PipeComSendn( PCom *to, const char *data, int n )
+{
+    int	nb = 0;
+    if( ! Check(to) )
+	return nb;
+
+    nb = fwrite( data, 1, n, to->fWrit );
+    fflush( to->fWrit );
+    return nb;
+}
+
+
+int PipeComReceive( PCom *from, char *data, int max )
+{
+    if( ! Check(from) )
+	return 0;
+    if( ! data ) {
+      fprintf( stderr, "PipeComReceive: Invalid data pointer\n" );
+      fflush( stderr );
+      return 0;
+    }
+    if( fgets( data, max, from->fRead ) )
+	return strlen(data);
+    return 0;
+}
+
+
+
+int PipeComClose( PCom *to )
+{
+    if( ! Check(to) )
+	return 0;
+    fclose( to->fRead );
+    fclose( to->fWrit );
+    free( to );
+    return 1;
+}
+
+
+
+int PipeComWaitFor( PCom *from, char *what )
+{
+    char	buffer[256];
+    do {
+	if( ! PipeComReceive( from, buffer, 256 ) )
+	    return 0;
+    } while( strcmp( buffer, what ) );
+    return 1;
+}
+
+
+
+// Local Variables:
+// coding: iso-8859-1
+// mode: C++
+// c-file-style: "Stroustrup"
+// fill-column: 80
+// End: