Link with $(CXX), not the build host g++.

diff -Nrup a/Makefile b/Makefile
--- a/Makefile	2008-04-05 20:05:45.000000000 +0200
+++ b/Makefile	2026-10-22 17:22:43.132887756 +0200
@@ -22,28 +22,28 @@ all:	mvclpf24.so mvchpf24.so cs_phaser.s
 
 
 mvclpf24.so:	mvclpf24.o mvclpf24_if.o exp2ap.o
-	g++ -shared  mvclpf24.o mvclpf24_if.o exp2ap.o -o mvclpf24.so
+	$(CXX) -shared  mvclpf24.o mvclpf24_if.o exp2ap.o -o mvclpf24.so
 
 mvclpf24.o:	ladspaplugin.h mvclpf24.h
 mvclpf24_if.o:	ladspaplugin.h mvclpf24.h
 
 
 mvchpf24.so:	mvchpf24.o mvchpf24_if.o exp2ap.o
-	g++ -shared  mvchpf24.o mvchpf24_if.o exp2ap.o -o mvchpf24.so
+	$(CXX) -shared  mvchpf24.o mvchpf24_if.o exp2ap.o -o mvchpf24.so
 
 mvchpf24.o:	ladspaplugin.h mvchpf24.h
 mvchpf24_if.o:	ladspaplugin.h mvchpf24.h
 
 
 cs_phaser.so:	cs_phaser.o cs_phaser_if.o exp2ap.o
-	g++ -shared cs_phaser.o cs_phaser_if.o exp2ap.o -o cs_phaser.so
+	$(CXX) -shared cs_phaser.o cs_phaser_if.o exp2ap.o -o cs_phaser.so
 
 cs_phaser.o:	ladspaplugin.h cs_phaser.h
 cs_phaser_if.o:	ladspaplugin.h cs_phaser.h
 
 
 cs_chorus.so:	cs_chorus.o cs_chorus_if.o exp2ap.o
-	g++ -shared  cs_chorus.o cs_chorus_if.o exp2ap.o -o cs_chorus.so
+	$(CXX) -shared  cs_chorus.o cs_chorus_if.o exp2ap.o -o cs_chorus.so
 
 cs_chorus.o:	ladspaplugin.h cs_chorus.h
 cs_chorus_if.o:	ladspaplugin.h cs_chorus.h