gh-36598: Relativize header imports
    
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I don't know why, but I've seen similar changes in other PRs and its
easier to use with meson. Should be all of them.

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URL: #36598
Reported by: Tobias Diez
Reviewer(s):

Author: Release Manager

src/sage/ext/cplusplus.pxd

@@ -8,7 +8,7 @@
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
 
-cdef extern from "sage/ext/ccobject.h":
+cdef extern from "ccobject.h":
     # Print representation of any C++ object
     str ccrepr[T](const T& x)
 

src/sage/libs/ntl/convert.pyx

@@ -23,7 +23,7 @@ Conversion between NTL's ``ZZ`` and various other types
 from sage.libs.gmp.mpz cimport mpz_init, mpz_clear
 from sage.libs.gmp.pylong cimport mpz_set_pylong
 
-cdef extern from "sage/libs/ntl/ntlwrap_impl.h":
+cdef extern from "ntlwrap_impl.h":
     void ZZ_to_mpz(mpz_t output, ZZ_c* x)
     void mpz_to_ZZ(ZZ_c *output, mpz_srcptr x)
 

src/sage/modular/arithgroup/farey_symbol.pyx

@@ -43,7 +43,7 @@ from sage.misc.cachefunc import cached_method
 from sage.structure.richcmp cimport richcmp_not_equal
 
 
-cdef extern from "sage/modular/arithgroup/sl2z.hpp":
+cdef extern from "sl2z.hpp":
     cppclass cpp_SL2Z "SL2Z":
         mpz_class a, b, c, d
         cpp_SL2Z(int, int, int, int)
@@ -53,7 +53,7 @@ cdef extern from "sage/modular/arithgroup/sl2z.hpp":
         mpz_class c()
         mpz_class d()
 
-cdef extern from "sage/modular/arithgroup/farey.hpp":
+cdef extern from "farey.hpp":
     cppclass is_element_Gamma0:
         is_element_Gamma0(int)
     cppclass is_element_Gamma1:

src/sage/rings/padics/padic_capped_absolute_element.pyx

@@ -25,7 +25,7 @@ include "CA_template.pxi"
 from sage.libs.pari.convert_gmp cimport new_gen_from_padic
 from sage.rings.finite_rings.integer_mod import Mod
 
-cdef extern from "sage/rings/padics/transcendantal.c":
+cdef extern from "transcendantal.c":
     cdef void padiclog(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp_Newton(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, unsigned long precinit, const mpz_t modulo)

src/sage/rings/padics/padic_capped_relative_element.pyx

@@ -29,7 +29,7 @@ from sage.libs.pari.convert_gmp cimport new_gen_from_padic
 from sage.rings.finite_rings.integer_mod import Mod
 from sage.rings.padics.pow_computer cimport PowComputer_class
 
-cdef extern from "sage/rings/padics/transcendantal.c":
+cdef extern from "transcendantal.c":
     cdef void padiclog(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp_Newton(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, unsigned long precinit, const mpz_t modulo)

src/sage/rings/padics/padic_fixed_mod_element.pyx

@@ -27,7 +27,7 @@ include "FM_template.pxi"
 from sage.libs.pari.convert_gmp cimport new_gen_from_padic
 from sage.rings.finite_rings.integer_mod import Mod
 
-cdef extern from "sage/rings/padics/transcendantal.c":
+cdef extern from "transcendantal.c":
     cdef void padiclog(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp_Newton(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, unsigned long precinit, const mpz_t modulo)

src/sage/rings/padics/padic_floating_point_element.pyx

@@ -25,7 +25,7 @@ from sage.libs.pari.all import pari
 from sage.libs.pari.convert_gmp cimport new_gen_from_padic
 from sage.rings.finite_rings.integer_mod import Mod
 
-cdef extern from "sage/rings/padics/transcendantal.c":
+cdef extern from "transcendantal.c":
     cdef void padicexp(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, const mpz_t modulo)
     cdef void padicexp_Newton(mpz_t ans, const mpz_t a, unsigned long p, unsigned long prec, unsigned long precinit, const mpz_t modulo)