--- a/pico/Makefile.am
+++ b/pico/Makefile.am
@@ -34,42 +34,6 @@ libttspico_la_SOURCES = \
 	lib/picotrns.c \
 	lib/picowa.c
 
-libttspico_ladir = $(includedir)
-libttspico_la_HEADERS = \
-    lib/picoacph.h \
-    lib/picoapid.h \
-    lib/picoapi.h \
-    lib/picobase.h \
-    lib/picocep.h \
-    lib/picoctrl.h \
-    lib/picodata.h \
-    lib/picodbg.h \
-    lib/picodefs.h \
-    lib/picodsp.h \
-    lib/picoextapi.h \
-    lib/picofftsg.h \
-    lib/picokdbg.h \
-    lib/picokdt.h \
-    lib/picokfst.h \
-    lib/picoklex.h \
-    lib/picoknow.h \
-    lib/picokpdf.h \
-    lib/picokpr.h \
-    lib/picoktab.h \
-    lib/picoos.h \
-    lib/picopal.h \
-    lib/picopam.h \
-    lib/picopltf.h \
-    lib/picopr.h \
-    lib/picorsrc.h \
-    lib/picosa.h \
-    lib/picosig2.h \
-    lib/picosig.h \
-    lib/picospho.h \
-    lib/picotok.h \
-    lib/picotrns.h \
-    lib/picowa.h
-
 libttspico_la_LIBADD = -lm
 
 picolangdir = $(datadir)/pico/lang