alsa support is conditional

This commit updates the makefile and the documentation to explain how to
build alsa support.  It has not been fully tested, so it is not built by
default.  Also, I was able to remove the conditional compile directives
from the source.

Makefile

@@ -1,23 +1,30 @@
-INSTALL = install
-
-CFLAGS ?= -DUSE_ALSA
-SRCS = \
-	cli.c \
-	alsa.c \
-	espeakup.c  \
-	espeak_sound.c \
-	queue.c \
-		softsynth.c \
-	synth.c
-
-OBJS = $(SRCS:.c=.o)
-
-LDLIBS = -lespeak -lasound
+CFLAGS += -Wall
+LDLIBS = -lespeak
 
 PREFIX = /usr
 MANDIR = $(PREFIX)/share/man/man8
 BINDIR = $(PREFIX)/bin
 
+INSTALL = install
+
+ALSA_SRCS = alsa.c
+ESPEAK_SRCS = espeak_sound.c
+SRCS = \
+	cli.c \
+	espeakup.c  \
+	queue.c \
+		softsynth.c \
+	synth.c
+
+ifeq ($(AUDIO),alsa)
+SRCS += $(ALSA_SRCS)
+LDLIBS += -lasound
+else
+SRCS += $(ESPEAK_SRCS)
+endif
+
+OBJS = $(SRCS:.c=.o)
+
 all: espeakup
 
 install: espeakup
@@ -27,7 +34,7 @@ install: espeakup
 	$(INSTALL) -m 0644 espeakup.8 $(DESTDIR)$(MANDIR)
 
 clean:
-	$(RM) $(OBJS)
+	$(RM) *.o
 
 distclean: clean
 	$(RM) espeakup
@@ -44,5 +51,6 @@ softsynth.o: softsynth.c espeakup.h
 
 synth.o: synth.c espeakup.h
 
-%.o: %.c
-	$(CC) -c -Wall $(CFLAGS) $(CPPFLAGS) -o $@ $< 
+alsa.o: alsa.c espeakup.h
+
+espeak_sound.o: espeak_sound.c espeakup.h

README

@@ -25,6 +25,17 @@ To install espeakup, first cd into the directory where you
 unpacked the tarball, then issue make to compile the program.  Once this
 is done, as root, issue make install.  This will install espeakup in /usr/bin.
 
+ALSA SUPPORT
+============
+
+Direct support for alsa was just contributed to this project; I would
+like to thank Chris Brannon for his work on this.  Currently,, it is in
+the early stages, so if you have any suggestions or patches, I am
+definitely interested.
+
+To build with alsa support, add "AUDIO=alsa" to the make command when you
+compile the program.
+
 Starting Up
 ===========
 

alsa.c

@@ -22,7 +22,6 @@
  * Description: Produce audio by calling the ALSA library directly.
 */
 
-#ifdef USE_ALSA
 #include <stdio.h>
 #include <stdlib.h>
 #include <limits.h>
@@ -146,4 +145,3 @@ int init_audio(void)
 	audio_callback = alsa_play_callback;
 	return 0;
 }
-#endif

espeak_sound.c

@@ -1,4 +1,3 @@
-#ifndef USE_ALSA
 #include "espeakup.h"
 int init_audio(void)
 {
@@ -6,4 +5,3 @@ int init_audio(void)
 	audio_callback = NULL;
 	return 0;
 }
-#endif