graphics/tesseract: Fix build on armv6/armv7

Tesseract requires the <asm/hwcap.h> header to detect the availability
of NEON instructions on armv7.  This commit adds a patch to use the
appropriate FreeBSD interface for this purpose.  This issue has already
been reported to up stream.

See also:	tesseract-ocr/tesseract#3782
See also:	PR #263003

PR:		263004
Approved by:	portmgr (build fix blanket)

graphics/tesseract/files/patch-src_arch_simddetect.cpp

@@ -0,0 +1,41 @@
+--- src/arch/simddetect.cpp.orig	2022-04-02 13:06:33 UTC
++++ src/arch/simddetect.cpp
+@@ -55,10 +55,12 @@
+ #if defined(HAVE_NEON) && !defined(__aarch64__)
+ #  ifdef ANDROID
+ #    include <cpu-features.h>
+-#  else
+-/* Assume linux */
++#  elif defined(__linux__)
+ #    include <asm/hwcap.h>
+ #    include <sys/auxv.h>
++#  elif defined(__FreeBSD__)
++#    include <sys/auxv.h>
++#    include <sys/elf.h>
+ #  endif
+ #endif
+
+@@ -85,7 +87,7 @@ SIMDDetect SIMDDetect::detector;
+ bool SIMDDetect::neon_available_ = true;
+ #elif defined(HAVE_NEON)
+ // If true, then Neon has been detected.
+-bool SIMDDetect::neon_available_;
++bool SIMDDetect::neon_available_ = false;
+ #else
+ // If true, then AVX has been detected.
+ bool SIMDDetect::avx_available_;
+@@ -216,9 +218,12 @@ SIMDDetect::SIMDDetect() {
+     if (family == ANDROID_CPU_FAMILY_ARM)
+       neon_available_ = (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON);
+   }
+-#  else
+-  /* Assume linux */
++#  elif defined(__linux__)
+   neon_available_ = getauxval(AT_HWCAP) & HWCAP_NEON;
++#  elif defined(__FreeBSD__)
++  unsigned long hwcap = 0;
++  elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
++  neon_available_ = hwcap & HWCAP_NEON;
+ #  endif
+ #endif
+