Qt5 fails to load module tslib because pthres.so - qt5

Question

I'm running into an odd problem on an embedded device. When I run qt5
someQt5App -platform eglfs -plugin tslib
QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv_open failed
QIconvCodec::convertToUnicode: using Latin-1 for conversion, iconv_open failed
EGLFS: Unable to query physical screen size, defaulting to 100 dpi.
EGLFS: To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).
QTsLibMouseHandler "tslib" ""
Loading module /usr/lib/ts//input.so
Loading module /usr/lib/ts//pthres.so
Couldnt load module pthres
Error configuring
: No such file or directory
So this first made me think there is no pthres.so, but there is, I checked. I think pthres is failing to load properly and I'm not sure why. I have some strace output
write(1, "Loading module /usr/lib/ts//pthr"..., 38) = 38
open("/usr/lib/ts//pthres.so", O_RDONLY|O_CLOEXEC) = 13
read(13, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0p\5\0\0004\0\0\0"..., 512) = 512
fstat64(13, {st_mode=S_IFREG|0755, st_size=3940, ...}) = 0
mmap2(NULL, 35424, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 13, 0) = 0x2aae4000
mprotect(0x2aae5000, 28672, PROT_NONE) = 0
mmap2(0x2aaec000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 13, 0) = 0x2aaec000
close(13) = 0
munmap(0x2aae4000, 35424) = 0
write(2, "Couldnt load module pthres\n", 27) = 27
close(12) = 0
munmap(0x2aae0000, 4096) = 0
write(2, "Error configuring\n: No such file"..., 46) = 46
write(5, "\1\0\0\0\0\0\0\0", 8) = 8
So here I can see that the module loaded, and for whatever reason closed and I'm not sure why it closed.
Pthres is available
# ls -l /usr/lib/ts/pthres.so
-rwxr-xr-x 1 root root 3940 Feb 24 2014 /usr/lib/ts/pthres.so
just for reference i moved pthres, here is the strace from that attempt
write(1, "Loading module /usr/lib/ts//pthr"..., 38) = 38
open("/usr/lib/ts//pthres.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
write(2, "Couldnt load module pthres\n", 27) = 27
close(12) = 0
munmap(0x2abaa000, 4096) = 0
write(2, "Error configuring\n: No such file"..., 46) = 46
Device environment (works with qt4/qws)
# env
TSLIB_TSDEVICE=/dev/input/event2
USER=root
OLDPWD=/
HOME=/
PAGER=/usr/bin/less
TERM=vt102
PATH=/sbin:/usr/sbin:/bin:/usr/bin
TSLIB_CONFFILE=/etc/ts.conf
MANPAGER=/usr/bin/less
SHELL=/bin/sh
PWD=/usr/lib/ts
TZ=US/Eastern
POINTERCAL_FILE=/thermo/pointercal
TSLIB_CALIBFILE=/thermo/pointercal

Answer 1

Figured it out, it turns out that tslib's errors were misleading. It was a linking error with pthres and someone somewhere has a patch for it.
diff --git a/plugins/Makefile.am b/plugins/Makefile.am
index c54a690..4aedac2 100644
## -107,15 +107,19 ## pluginexec_LTLIBRARIES = \
variance_la_SOURCES = variance.c
variance_la_LDFLAGS = -module $(LTVSN)
+variance_la_LIBADD = $(top_builddir)/src/libts.la
dejitter_la_SOURCES = dejitter.c
dejitter_la_LDFLAGS = -module $(LTVSN)
+dejitter_la_LIBADD = $(top_builddir)/src/libts.la
linear_la_SOURCES = linear.c
linear_la_LDFLAGS = -module $(LTVSN)
+linear_la_LIBADD = $(top_builddir)/src/libts.la
pthres_la_SOURCES = pthres.c
pthres_la_LDFLAGS = -module $(LTVSN)
+pthres_la_LIBADD = $(top_builddir)/src/libts.la
# hw access
corgi_la_SOURCES = corgi-raw.c

Answer 2

You can either modify the makfile.am as Kevin has mentioned or you can run the below command and run your application without any hastle.
export LD_PRELOAD=/usr/lib/libts-x.x.so.x.x.x
where x is the version of tslib you are using