levmar uses Xgemm, a BLAS function, if built with -DHAVE_LAPACK
--- hugin-2019.2.0/CMakeLists.txt.orig	2020-08-20 22:48:22.907952199 +0200
+++ hugin-2019.2.0/CMakeLists.txt	2020-08-20 22:49:36.971598517 +0200
@@ -472,9 +472,15 @@
   FIND_PACKAGE(LAPACK)
   IF(LAPACK_FOUND)
     MESSAGE(STATUS "LAPACK found (${LAPACK_LIBRARIES})")
-  ELSE(LAPACK_FOUND)
-    MESSAGE(STATUS "LAPACK not found, using LU-based solver")
+    FIND_PACKAGE(BLAS)
+    IF(BLAS_FOUND)
+      MESSAGE(STATUS "BLAS found (${BLAS_LIBRARIES})")
+    ENDIF(BLAS_FOUND)
   ENDIF(LAPACK_FOUND)
+  IF(NOT BLAS_FOUND OR NOT LAPACK_FOUND)
+    MESSAGE(STATUS "BLAS or LAPACK not found, using LU-based solver")
+    SET(LAPACK_FOUND OFF)
+  ENDIF(NOT BLAS_FOUND OR NOT LAPACK_FOUND)
 ENDIF(ENABLE_LAPACK)
 
 OPTION(USE_GDKBACKEND_X11 "Enforce GDK_BACKEND=x11 for Hugin as workaround for wxWidgets bug (not supporting wxGLCanvas on Wayland)" OFF)
--- hugin-2019.2.0/src/hugin_base/CMakeLists.txt.orig	2020-08-20 21:56:15.436078470 +0200
+++ hugin-2019.2.0/src/hugin_base/CMakeLists.txt	2020-08-20 21:58:58.028292039 +0200
@@ -168,7 +168,7 @@
 
 TARGET_LINK_LIBRARIES(huginbase huginlevmar ${VIGRA_LIBRARIES} 
         ${Boost_LIBRARIES} ${EXIV2_LIBRARIES} ${PANO_LIBRARIES}
-        ${TIFF_LIBRARIES} ${LAPACK_LIBRARIES}
+        ${TIFF_LIBRARIES} ${BLAS_LIBRARIES} ${LAPACK_LIBRARIES}
         ${OPENGL_GLEW_LIBRARIES} Threads::Threads
         ${SQLITE3_LIBRARIES} ${LCMS2_LIBRARIES})