Our package build process currently has a significant flaw: we first run `setup.py`, recording all compilation commands, then we rewrite these compilation commands to invoke `emcc` and replay them, and then we pray that the cross compiled executables ended up in the right place to go into the wheel. This is not a good strategy because the build script is allowed to implement arbitrary logic, and if it moves, renames, etc any of the output files then we lose track of them. This has repeatedly caused difficulty for us.

However, we also make no particularly significant use of the two pass approach. We can just do the simpler thing: capture the compiler commands as they occur, modify them as needed, and then run the fixed command.

I also added a patch to fix the numpy feature detection for wasm so that we don't have to include `_npyconfig.h` and `config.h`, numpy can generate them in the way it would for a native build. I opened a numpy PR that would fix the detection for us upstream:
https://github.com/numpy/numpy/pull/21154

This clears the way for us to switch to using pypa/build (as @henryiii has suggested) by removing our dependence on specific setuptools behavior.

This is on top of #2238.
No replay. Our package build process currently has a significant flaw: we first run `setup.py`, recording all compilation commands, then we rewrite these compilation commands to invoke `emcc` and replay them, and then we pray that the cross compiled executables ended up in the right place to go into the wheel. This is not a good strategy because the build script is allowed to implement arbitrary logic, and if it moves, renames, etc any of the output files then we lose track of them. This has repeatedly caused difficulty for us.

However, we also make no particularly significant use of the two pass approach. We can just do the simpler thing: capture the compiler commands as they occur, modify them as needed, and then run the fixed command.

I also added a patch to fix the numpy feature detection for wasm so that we don't have to include `_npyconfig.h` and `config.h`, numpy can generate them in the way it would for a native build. I opened a numpy PR that would fix the detection for us upstream:
https://github.com/numpy/numpy/pull/21154

This clears the way for us to switch to using pypa/build (as @henryiii has suggested) by removing our dependence on specific setuptools behavior.

This is on top of #2238.
# -*- Makefile -*-
####################################################################
#  LAPACK make include file.                                       #
#  LAPACK, Version 3.2.1                                           #
#  June 2009		                                               #
####################################################################
#
# See the INSTALL/ directory for more examples.
#
SHELL = /bin/sh
#
#  The machine (platform) identifier to append to the library names
#
# WA for WebAssembly
PLAT = _WA
#
#  Modify the FORTRAN and OPTS definitions to refer to the
#  compiler and desired compiler options for your machine.  NOOPT
#  refers to the compiler options desired when NO OPTIMIZATION is
#  selected.  Define LOADER and LOADOPTS to refer to the loader
#  and desired load options for your machine.
#
#######################################################
# This is used to compile C library
#CC        = gcc  # inherit $CC from emmake
# if no wrapping of the blas library is needed, uncomment next line
#CC        = gcc -DNO_BLAS_WRAP
CFLAGS    = -O3 -I$(TOPDIR)/INCLUDE -fPIC -DNO_BLAS_WRAP
LDFLAGS	  = -O3
LOADER    = $(CC)
LOADOPTS  =
NOOPT     = -O0 -I$(TOPDIR)/INCLUDE -fPIC
DRVCFLAGS = $(CFLAGS)
F2CCFLAGS = $(CFLAGS)
#######################################################################

#
# Timer for the SECOND and DSECND routines
#
# Default : SECOND and DSECND will use a call to the EXTERNAL FUNCTION ETIME
# TIMER    = EXT_ETIME
# For RS6K : SECOND and DSECND will use a call to the EXTERNAL FUNCTION ETIME_
# TIMER    = EXT_ETIME_
# For gfortran compiler: SECOND and DSECND will use a call to the INTERNAL FUNCTION ETIME
# TIMER    = INT_ETIME
# If your Fortran compiler does not provide etime (like Nag Fortran Compiler, etc...)
# SECOND and DSECND will use a call to the Fortran standard INTERNAL FUNCTION CPU_TIME
TIMER    = INT_CPU_TIME
# If neither of this works...you can use the NONE value... In that case, SECOND and DSECND will always return 0
# TIMER     = NONE
#
#  The archiver and the flag(s) to use when building archive (library)
#  If you system has no ranlib, set RANLIB = echo.
#
ARCH     = $(AR)
ARCHFLAGS= cr
#RANLIB   = ranlib
#
#  The location of BLAS library for linking the testing programs.
#  The target's machine-specific, optimized BLAS library should be
#  used whenever possible.
#
BLASLIB      = ../../blas$(PLAT).a
#
#  Location of the extended-precision BLAS (XBLAS) Fortran library
#  used for building and testing extended-precision routines.  The
#  relevant routines will be compiled and XBLAS will be linked only if
#  USEXBLAS is defined.
#
# USEXBLAS    = Yes
XBLASLIB     =
# XBLASLIB    = -lxblas
#
#  Names of generated libraries.
#
LAPACKLIB    = lapack$(PLAT).a
F2CLIB       = ../../F2CLIBS/libf2c.a
TMGLIB       = tmglib$(PLAT).a
EIGSRCLIB    = eigsrc$(PLAT).a
LINSRCLIB    = linsrc$(PLAT).a

# -*- Makefile -*-
####################################################################
#  LAPACK make include file.                                       #
#  LAPACK, Version 3.2.1                                           #
#  June 2009		                                               #
####################################################################
#
# See the INSTALL/ directory for more examples.
#
SHELL = /bin/sh
#
#  The machine (platform) identifier to append to the library names
#
# WA for WebAssembly
PLAT = _WA
#
#  Modify the FORTRAN and OPTS definitions to refer to the
#  compiler and desired compiler options for your machine.  NOOPT
#  refers to the compiler options desired when NO OPTIMIZATION is
#  selected.  Define LOADER and LOADOPTS to refer to the loader
#  and desired load options for your machine.
#
#######################################################
# This is used to compile C library
#CC        = gcc  # inherit $CC from emmake
# if no wrapping of the blas library is needed, uncomment next line
#CC        = gcc -DNO_BLAS_WRAP
CFLAGS    = -O3 -I$(TOPDIR)/INCLUDE -fPIC -DNO_BLAS_WRAP
LDFLAGS	  = -O3
LOADER    = $(CC)
LOADOPTS  =
NOOPT     = -O0 -I$(TOPDIR)/INCLUDE -fPIC
DRVCFLAGS = $(CFLAGS)
F2CCFLAGS = $(CFLAGS)
#######################################################################

#
# Timer for the SECOND and DSECND routines
#
# Default : SECOND and DSECND will use a call to the EXTERNAL FUNCTION ETIME
# TIMER    = EXT_ETIME
# For RS6K : SECOND and DSECND will use a call to the EXTERNAL FUNCTION ETIME_
# TIMER    = EXT_ETIME_
# For gfortran compiler: SECOND and DSECND will use a call to the INTERNAL FUNCTION ETIME
# TIMER    = INT_ETIME
# If your Fortran compiler does not provide etime (like Nag Fortran Compiler, etc...)
# SECOND and DSECND will use a call to the Fortran standard INTERNAL FUNCTION CPU_TIME
TIMER    = INT_CPU_TIME
# If neither of this works...you can use the NONE value... In that case, SECOND and DSECND will always return 0
# TIMER     = NONE
#
#  The archiver and the flag(s) to use when building archive (library)
#  If you system has no ranlib, set RANLIB = echo.
#
ARCH     = $(AR)
ARCHFLAGS= cr
#RANLIB   = ranlib
#
#  The location of BLAS library for linking the testing programs.
#  The target's machine-specific, optimized BLAS library should be
#  used whenever possible.
#
BLASLIB      = ../../blas$(PLAT).a
#
#  Location of the extended-precision BLAS (XBLAS) Fortran library
#  used for building and testing extended-precision routines.  The
#  relevant routines will be compiled and XBLAS will be linked only if
#  USEXBLAS is defined.
#
# USEXBLAS    = Yes
XBLASLIB     =
# XBLASLIB    = -lxblas
#
#  Names of generated libraries.
#
LAPACKLIB    = lapack$(PLAT).a
F2CLIB       = ../../F2CLIBS/libf2c.a
TMGLIB       = tmglib$(PLAT).a
EIGSRCLIB    = eigsrc$(PLAT).a
LINSRCLIB    = linsrc$(PLAT).a
