With newer versions of emscripten, linker errors surface eariler.
This makes it easier to find function pointer cast errors without
having to execute the bad code path -- the errors happen when the
wasm modules are linked (at load time in the browser)

Anyways, this fixes more linker errors. Mostly the problems have
to do with LAPACK functions that take string arguments. Most
LAPACK functions that take string arguments use them as enums and
only care about the first character of the string. Because of the
way that f2c works, we need to replace these strings with the ascii
code of the first character so we should replace:

sTRSV( 'UPPER', 'NOTRANS', 'NONUNIT', J, H, LDH, Y, 1 )
==>
CALL sTRSV( 85, 78, 78, J, H, LDH, Y, 1 )

where 85 and 78 are the ascii codes of U and N. Various character
variables are subbed into being integer variables. The two
functions `ilaenv` and `xerbla` expect actual C strings as an
argument, but it is very annoying to produce C strings so instead
I added wrapper functions ilaenvf2c and xerblaf2c to clapack and
instead of calling ilaenv and xerbla we call the f2c versions.

Fix scipy linking errors. With newer versions of emscripten, linker errors surface eariler.
This makes it easier to find function pointer cast errors without
having to execute the bad code path -- the errors happen when the
wasm modules are linked (at load time in the browser)

Anyways, this fixes more linker errors. Mostly the problems have
to do with LAPACK functions that take string arguments. Most
LAPACK functions that take string arguments use them as enums and
only care about the first character of the string. Because of the
way that f2c works, we need to replace these strings with the ascii
code of the first character so we should replace:

sTRSV( 'UPPER', 'NOTRANS', 'NONUNIT', J, H, LDH, Y, 1 )
==>
CALL sTRSV( 85, 78, 78, J, H, LDH, Y, 1 )

where 85 and 78 are the ascii codes of U and N. Various character
variables are subbed into being integer variables. The two
functions `ilaenv` and `xerbla` expect actual C strings as an
argument, but it is very annoying to produce C strings so instead
I added wrapper functions ilaenvf2c and xerblaf2c to clapack and
instead of calling ilaenv and xerbla we call the f2c versions.

commit 12b131883a0505987b052cb58ee1320aed24aeb4
Author: Roman Yurchak <rth.yurchak@gmail.com>
Date:   Mon Mar 22 21:33:26 2021 +0100

    Use float error status without external includes in numpy
    
    A better solution would be to rely on FE_DIVBYZERO, FE_DIVBYZERO etc
    defined in musl's fenv.h (https://github.com/numpy/numpy/pull/12124)
    however these are not valid for emscripten
    (https://github.com/emscripten-core/emscripten/issues/13678)

diff --git a/numpy/core/src/npymath/ieee754.c.src b/numpy/core/src/npymath/ieee754.c.src
index 3f66b24a4..6beb63edc 100644
--- a/numpy/core/src/npymath/ieee754.c.src
+++ b/numpy/core/src/npymath/ieee754.c.src
@@ -682,7 +682,8 @@ void npy_set_floatstatus_invalid(void)
 }
 
 #elif defined(_MSC_VER) || (defined(__osf__) && defined(__alpha)) || \
-      defined (__UCLIBC__) || (defined(__arc__) && defined(__GLIBC__))
+      defined (__UCLIBC__) || (defined(__arc__) && defined(__GLIBC__)) || \
+      defined(__EMSCRIPTEN__)
 
 /*
  * By using a volatile floating point value,
@@ -719,37 +720,22 @@ void npy_set_floatstatus_invalid(void)
 }
 
 /* MS Windows -----------------------------------------------------*/
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) || defined(__EMSCRIPTEN__)
 
 #include <float.h>
 
 int npy_get_floatstatus_barrier(char *param)
 {
-    /*
-     * By using a volatile, the compiler cannot reorder this call
-     */
-#if defined(_WIN64)
-    int fpstatus = _statusfp();
-#else
-    /* windows enables sse on 32 bit, so check both flags */
-    int fpstatus, fpstatus2;
-    _statusfp2(&fpstatus, &fpstatus2);
-    fpstatus |= fpstatus2;
-#endif
-    if (param != NULL) {
-        volatile char NPY_UNUSED(c) = *(char*)param;
-    }
-    return ((SW_ZERODIVIDE & fpstatus) ? NPY_FPE_DIVIDEBYZERO : 0) |
-           ((SW_OVERFLOW & fpstatus) ? NPY_FPE_OVERFLOW : 0) |
-           ((SW_UNDERFLOW & fpstatus) ? NPY_FPE_UNDERFLOW : 0) |
-           ((SW_INVALID & fpstatus) ? NPY_FPE_INVALID : 0);
+   /* 
+   TODO: This is a suboptimal implementation from numpy 1.15.4 that would lead
+   to issues like https://github.com/numpy/numpy/issues/12095 
+   */
+   return 0;
 }
 
 int npy_clear_floatstatus_barrier(char *param)
 {
     int fpstatus = npy_get_floatstatus_barrier(param);
-    _clearfp();
-
     return fpstatus;
 }
 

commit 12b131883a0505987b052cb58ee1320aed24aeb4
Author: Roman Yurchak <rth.yurchak@gmail.com>
Date:   Mon Mar 22 21:33:26 2021 +0100

    Use float error status without external includes in numpy
    
    A better solution would be to rely on FE_DIVBYZERO, FE_DIVBYZERO etc
    defined in musl's fenv.h (https://github.com/numpy/numpy/pull/12124)
    however these are not valid for emscripten
    (https://github.com/emscripten-core/emscripten/issues/13678)

diff --git a/numpy/core/src/npymath/ieee754.c.src b/numpy/core/src/npymath/ieee754.c.src
index 3f66b24a4..6beb63edc 100644
--- a/numpy/core/src/npymath/ieee754.c.src
+++ b/numpy/core/src/npymath/ieee754.c.src
@@ -682,7 +682,8 @@ void npy_set_floatstatus_invalid(void)
 }
 
 #elif defined(_MSC_VER) || (defined(__osf__) && defined(__alpha)) || \
-      defined (__UCLIBC__) || (defined(__arc__) && defined(__GLIBC__))
+      defined (__UCLIBC__) || (defined(__arc__) && defined(__GLIBC__)) || \
+      defined(__EMSCRIPTEN__)
 
 /*
  * By using a volatile floating point value,
@@ -719,37 +720,22 @@ void npy_set_floatstatus_invalid(void)
 }
 
 /* MS Windows -----------------------------------------------------*/
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) || defined(__EMSCRIPTEN__)
 
 #include <float.h>
 
 int npy_get_floatstatus_barrier(char *param)
 {
-    /*
-     * By using a volatile, the compiler cannot reorder this call
-     */
-#if defined(_WIN64)
-    int fpstatus = _statusfp();
-#else
-    /* windows enables sse on 32 bit, so check both flags */
-    int fpstatus, fpstatus2;
-    _statusfp2(&fpstatus, &fpstatus2);
-    fpstatus |= fpstatus2;
-#endif
-    if (param != NULL) {
-        volatile char NPY_UNUSED(c) = *(char*)param;
-    }
-    return ((SW_ZERODIVIDE & fpstatus) ? NPY_FPE_DIVIDEBYZERO : 0) |
-           ((SW_OVERFLOW & fpstatus) ? NPY_FPE_OVERFLOW : 0) |
-           ((SW_UNDERFLOW & fpstatus) ? NPY_FPE_UNDERFLOW : 0) |
-           ((SW_INVALID & fpstatus) ? NPY_FPE_INVALID : 0);
+   /* 
+   TODO: This is a suboptimal implementation from numpy 1.15.4 that would lead
+   to issues like https://github.com/numpy/numpy/issues/12095 
+   */
+   return 0;
 }
 
 int npy_clear_floatstatus_barrier(char *param)
 {
     int fpstatus = npy_get_floatstatus_barrier(param);
-    _clearfp();
-
     return fpstatus;
 }
 
